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Author Topic:   achieving WOT

litnin posted 07-28-2003 06:35 AM ET (US)
My 87' Montauk with the original Evinrude 90 v4 was only able to produce 4800 rpm's at WOT. It also seemed sluggish so I injected the engine with the OMC tuner in a can the night before. I noticed no improvement in the performance or ability to achieve WOT. After about twenty miles I did the Bigshot thing and put a bottle of Techron in and after a few miles, I noticed a definite improvement in the performance and I was able to get to 5000 rpm's. How important is it to get to 5500? I believe that is supposed to be WOT on my 90. Prop is a ss 13 3/8 x 17 OMC. While turning 5000 rpm's, my speed by GPS only showed 33 mph. Should I switch to another prop to improve top end? Maybe I am expecting too much from a sixteen year old engine. Input?
Thanks, Chris
Clark Roberts posted 07-28-2003 07:23 AM ET (US)
Chris, check that throttle linkages are providing full open throttle; raise engine so that anti-cavitation plate is approx 1" above keel; if still no 5500 rpm then go to reduced pitch prop (each one inch of pitch will net approx 200 rpm either up or down)... oh yes, check hull for barnicles/marine growth.. Happy Whalin'... Clark .. Spruce Creek Navy
JohnJ80 posted 07-28-2003 11:46 AM ET (US)
i agree with all of the above.
if you have never been able to get to the WOT max rpm specified for your engine then i would really look at the prop and motor positioning.
if this happened all of a sudden, then i would also have a compression test or leak down test done on your motor (after, of course, changing plugs). if you can't develop the compression, it will be like your motor is in wimpy mode. If that leaddown is bad, then it is probably time to look at valves or rings.
my first bet is the prop and motor position thing though.
j
Bigshot posted 07-28-2003 01:56 PM ET (US)
Well it sure as hell can't be valves!
My 90 would do almost 5300 with same prop and about 41mph. I would try more Techron or a carb rebuild and leave rpop alone. Raising the engine up is also good. Of course this is after you rule out a tired engine via compression test.
litnin posted 07-29-2003 08:03 PM ET (US)
OK guys, I jumped the gun and assumed that because I checked the compression a few months ago and also that it was doing 5000 RPM's (and not running badly at all) that the compression was still OK. Today I checked the compression and both of the left cylinders had 130 ea. The right top cylinder was 60 and the bottom right was 10.
I find it hard to fathom this as it was truly not running terribly. Could it be a blown head gasket causing this or possibly a reed valve? I am a MG car man with lots of mechanical experience but not a outboard motor man. I'm not afraid to start taking it apart if I can get some ideas as to where to start. By the way, what will the outcome be if I keep running it? The family vacation is to be at the NC coast August 8th. Lots of disappointed children to deal with. Gimme the word. Thanks, Chris
PS.. Hard to swallow that the rings would go to pieces on two cylinders at the same time.
flyguy posted 07-29-2003 08:27 PM ET (US)
take off the cylinder head and take a look at the gasket. if it's not the gasket then at least you can take a good look at the cylinders, pistons, rings, etc.
tgresla posted 07-29-2003 10:35 PM ET (US)
Is there an efficient cheap way to find out rpm's on an outboard (1997 Evinrude 30) that doesn't have a tach? I'm not sure if my engine is running correct at WOT.
Sorry this should probably be a new topic but since the motor experts were here I thought I'de ask.
bsmotril posted 07-29-2003 10:47 PM ET (US)
See if you can get hold of a cylinder leakdown tester. Pull the plugs from both holes in that bank, and pressurize the worst one. If you hear or feel air leaking from the other sparkplug hole, you have a bad gasket leaking between the cylinders. But as others said, you can just pull the heads and look also. On a high hour engine used in saltwater, the gaskets will go eventually, guranteed.
BillS
litnin posted 07-30-2003 08:21 AM ET (US)
My brother has a leak down tester and I will give it a shot. Not a good time to have to buy a new motor but is there EVER at good time. Bout'like waiting for financial security before having children. You'll never have them if you wait for that. Chris
jimh posted 07-30-2003 08:26 AM ET (US)
tgresla--not all engines can operate a tachometer. You generally need an engine that has been designed for electric start and battery charging.
The tachometer typically operates by connecting to the pulses coming off a stator coil that is trying to charge the battery. Without that feature, an electronic tachometer will not work.
Some small engines with pull start lack these components.
--jimh
tgresla posted 07-30-2003 08:30 AM ET (US)
My engine is electric start and charges a battery and does not have a pull start. I guess this means there should be an instrument (hopefully portable) that could read the RPM
jimh posted 07-30-2003 08:30 AM ET (US)
Discussion regarding performance of a boat and motor are best posted to the Classic Whaler: Performance forum.
You will find hundreds of message threads on this general topic (propeller selection) there.
litnin posted 07-30-2003 11:37 PM ET (US)
Went ahead and removed the right head of the engine and WOW! Piston top is really damaged on the upper piston with scoring on the cylinder walls. Lower piston also has some dings so evidently rings blew out the port after doing the damage. Looks like repower time to my dismay. Anyone out there feel that it is worth rebuilding a sixteen year old motor? If so, what are general costs? Have to make a decision.
Thank you all for the replies and advice, Chris
Bigshot posted 07-31-2003 10:06 AM ET (US)
Looking at $1500-2500 depending on who and "what" they rebuild. I personally do not care for rebuilds when you can get a real nice 2000 or 2001 for $4k or less. There is one here for sale delivered to your door for $4000 with all equip.
litnin posted 07-31-2003 10:56 AM ET (US)
Bigshot, give me names and places. I know that Ed's Marine Superstore in Virginia has Johnson 90 2s for 4495.00 without controls. Seems that depending on who you talk to, my existing controls and harness may or may not work. Everyone seems to try and get their hand in your pocket. Telling the truth is a rare commodity out in the business world, it seems. How about the dude in Marketplace selling the DF70's like yours for 5300.00? I need hole shot for pulling kids up on ski's. Thanks for your input. Chris
captbone posted 07-31-2003 11:31 AM ET (US)
Clean out the cylinders and slap it back together and run it until it dies. You can get the end of the summer out of it. Why not, the powerhead needs to be rebuilt anyway? Plus, for the 2 grand you wil drop on that, you may just as well put it towards a new motor. Who knows when the lower unit or something else will go. just my 2 cents.
Bigshot posted 07-31-2003 11:41 AM ET (US)
With damage like that I would not run it. The crank etc are stil good and you can still get $500 or so for it running. Your controls will still work. You need to get a wiring harness adapter for like $35 to connect your old style harness to new. You will also need to get a new tach or add the multifunction guage. New tachs with mulifunction can be had at surplus stores for like $60 or try e-Bay. If you want a good deal on a used or leftover, start calling EVERY marina in your state or nearby atates. I would also try e-Bay, they show up there quite often. If you are not "brand loyal" E-Bay will reveal some god deals.
Yes Bayracer is in the ballpark as long as that includes everything but controls. Controls cana also be found on E-Bay or you might be able to use yours. If you find a deal on an Evinrude or Johnson 4 stroke, you can yuse your controls, etc just like with a 2 stroke. The prop you have will also fit both Suzuki and Bombardier/OMC and the Zuki does well with a 17"prop especially if pulling a skier. My boat will pull up a 200lb skier no problem.
litnin posted 07-31-2003 03:36 PM ET (US)
Do the transom holes line on the DF70 Suzuki/Johnson with the old Evinrude V4 holes? I have driven Knothead's Montauk with the Johnson 90 2s and it has great hole shot. Top end for me is pretty unimportant. Wish I could drive one for comparison. Drilling new holes in the transom is a no-no for me.
I will be the engine installer on this one to save money.
Chris
Bodacious posted 07-31-2003 06:08 PM ET (US)
Hello Folks. I've been lurking here for quite some time and could not resist posting a reply to this thread. Out on boattradeonline. com , under the "motors" heading, there is a dealer in Havelock N.C. that is offering a new 02 Suzuki DF70 for 4995.00. No controls, no prop. It does come with the 6 year warranty. The dealership is Walsh Marine.
Good Luck
Don
Bigshot posted 08-01-2003 11:11 AM ET (US)
Is that Bayracer?
The bolt holes will line up as long as the original engine was not drilled for the blind holes.....then nothing will match. If you can see the lower bolts in the slots on the engine bracket....good. If no nuts are seen, then your best bet is a Manual jackplate for $150 and just drill through the aluminum jackplate and keep the old holes. I had to do his on my Newtauk being the dealer used the blind holes.....took 15 minutes to drill the plate.
nevada posted 08-01-2003 12:19 PM ET (US)
Bigshot,
Yes it is bayracer.
I found him on E-bay.
Joe
litnin posted 08-01-2003 02:06 PM ET (US)
Must make a decision. It will either be the Johnson 90 2s because of worry about hole shot for pulling up a skier OR the DF70 from Bayracer, mostly because of the six year warranty. Difference will be basically 1000k more for the DF70 because of higher initial cost plus having to pay NC sales tax. Any opinions?
Bigshot posted 08-01-2003 02:15 PM ET (US)
Unless you have some "husky" children, get the DF70. You will love it and in about 600 hours make up the price difference in fuel savings. I would not trade my 70 for any 2 stroke. You can still use your old prop on the zuki, just have to shim it some. The sales tax is almost same as shipping so look at it that way.....6 in one hand....:)
PS is he selling it for $4995 or $5300?
litnin posted 08-01-2003 05:05 PM ET (US)
Evidently 4995.00 for the boattrader.com crowd and 5300.00 for the Whaler crowd. Sounds like discrimination. Anyway, maybe I misunderstood your earlier post. If I buy a Johnson 90 2s, and my existing engine uses the blind lower holes, will it not line up? Please advise. Pressure is on. Chris
Gene in NC posted 08-04-2003 07:04 AM ET (US)
My '87 sounds identical to yours, both configuration and performance. Power head reportedly rebuilt before I bot it. We fished the Crocker tournament 7/26, ran it in FL this winter and my son is running it all over the Wilmington area right now. Need to do compression check and will report.
Forget the 70 go with a 90. Kids grow. Kids want to invite friends. Kids want to ski double.
Ran a '66 Johnson 100 on Sakonnet for 30 years. Jerked skiers out of the water. Set engine angle down to lift the stern not the bow. Pulled double slalom skiers w/o prob including spectators in the boat. With engine tucked in ran 36 at 5500. Plenty fast. Just left it that way. No pt in the old days.
Run the engine on your vacation. Damage already done. Even if it blows completely you will have a complete set of spares for the replacement. Plenty time to rebuild yourself or find another. That engine common as dirt.
If you can keep a MG going your can rebuild that power head. A friend did his. If you like I will get his report on out of pocket cost.
Bigshot posted 08-04-2003 10:09 AM ET (US)
Gene my point exactly....your old 100 did 36 and you loved it. The 70 will do 39, so why go with a 90 and do 42 and burn twice the gas?
The Johnson will use your controls, prop, key, etc. You just have to buy a $35 wiring harness adapter and a systems check guage.....period. Try eds on that engine.
I heard the $5300 gets it installed, if so not a bad gig.
litnin posted 08-04-2003 10:23 AM ET (US)
Bum at almost local dealer said that nothing I have will work with the new motor and that even my oil tank would need replacing. If I told my customers anything other than the truth, I wouldn't expect to have my customers very long. Thanks for the info. Big's, if I decide to buy the 90 2s, is an extended warranty a good thing to consider. Trust your judgement. Chris Thanks to Gene also.
Bigshot posted 08-04-2003 11:31 AM ET (US)
I thought they were offering 5 year with Bombardier. IF not it REALLY depends on price. I personally think they are a waste of money but if a 5 year is $600 then.....

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Author	Topic: achieving WOT
litnin	posted 07-28-2003 06:35 AM ET (US) My 87' Montauk with the original Evinrude 90 v4 was only able to produce 4800 rpm's at WOT. It also seemed sluggish so I injected the engine with the OMC tuner in a can the night before. I noticed no improvement in the performance or ability to achieve WOT. After about twenty miles I did the Bigshot thing and put a bottle of Techron in and after a few miles, I noticed a definite improvement in the performance and I was able to get to 5000 rpm's. How important is it to get to 5500? I believe that is supposed to be WOT on my 90. Prop is a ss 13 3/8 x 17 OMC. While turning 5000 rpm's, my speed by GPS only showed 33 mph. Should I switch to another prop to improve top end? Maybe I am expecting too much from a sixteen year old engine. Input? Thanks, Chris
Clark Roberts	posted 07-28-2003 07:23 AM ET (US) Chris, check that throttle linkages are providing full open throttle; raise engine so that anti-cavitation plate is approx 1" above keel; if still no 5500 rpm then go to reduced pitch prop (each one inch of pitch will net approx 200 rpm either up or down)... oh yes, check hull for barnicles/marine growth.. Happy Whalin'... Clark .. Spruce Creek Navy
JohnJ80	posted 07-28-2003 11:46 AM ET (US) i agree with all of the above. if you have never been able to get to the WOT max rpm specified for your engine then i would really look at the prop and motor positioning. if this happened all of a sudden, then i would also have a compression test or leak down test done on your motor (after, of course, changing plugs). if you can't develop the compression, it will be like your motor is in wimpy mode. If that leaddown is bad, then it is probably time to look at valves or rings. my first bet is the prop and motor position thing though. j
Bigshot	posted 07-28-2003 01:56 PM ET (US) Well it sure as hell can't be valves! My 90 would do almost 5300 with same prop and about 41mph. I would try more Techron or a carb rebuild and leave rpop alone. Raising the engine up is also good. Of course this is after you rule out a tired engine via compression test.
litnin	posted 07-29-2003 08:03 PM ET (US) OK guys, I jumped the gun and assumed that because I checked the compression a few months ago and also that it was doing 5000 RPM's (and not running badly at all) that the compression was still OK. Today I checked the compression and both of the left cylinders had 130 ea. The right top cylinder was 60 and the bottom right was 10. I find it hard to fathom this as it was truly not running terribly. Could it be a blown head gasket causing this or possibly a reed valve? I am a MG car man with lots of mechanical experience but not a outboard motor man. I'm not afraid to start taking it apart if I can get some ideas as to where to start. By the way, what will the outcome be if I keep running it? The family vacation is to be at the NC coast August 8th. Lots of disappointed children to deal with. Gimme the word. Thanks, Chris PS.. Hard to swallow that the rings would go to pieces on two cylinders at the same time.
flyguy	posted 07-29-2003 08:27 PM ET (US) take off the cylinder head and take a look at the gasket. if it's not the gasket then at least you can take a good look at the cylinders, pistons, rings, etc.
tgresla	posted 07-29-2003 10:35 PM ET (US) Is there an efficient cheap way to find out rpm's on an outboard (1997 Evinrude 30) that doesn't have a tach? I'm not sure if my engine is running correct at WOT. Sorry this should probably be a new topic but since the motor experts were here I thought I'de ask.
bsmotril	posted 07-29-2003 10:47 PM ET (US) See if you can get hold of a cylinder leakdown tester. Pull the plugs from both holes in that bank, and pressurize the worst one. If you hear or feel air leaking from the other sparkplug hole, you have a bad gasket leaking between the cylinders. But as others said, you can just pull the heads and look also. On a high hour engine used in saltwater, the gaskets will go eventually, guranteed. BillS
litnin	posted 07-30-2003 08:21 AM ET (US) My brother has a leak down tester and I will give it a shot. Not a good time to have to buy a new motor but is there EVER at good time. Bout'like waiting for financial security before having children. You'll never have them if you wait for that. Chris
jimh	posted 07-30-2003 08:26 AM ET (US) tgresla--not all engines can operate a tachometer. You generally need an engine that has been designed for electric start and battery charging. The tachometer typically operates by connecting to the pulses coming off a stator coil that is trying to charge the battery. Without that feature, an electronic tachometer will not work. Some small engines with pull start lack these components. --jimh
tgresla	posted 07-30-2003 08:30 AM ET (US) My engine is electric start and charges a battery and does not have a pull start. I guess this means there should be an instrument (hopefully portable) that could read the RPM
jimh	posted 07-30-2003 08:30 AM ET (US) Discussion regarding performance of a boat and motor are best posted to the Classic Whaler: Performance forum. You will find hundreds of message threads on this general topic (propeller selection) there.
litnin	posted 07-30-2003 11:37 PM ET (US) Went ahead and removed the right head of the engine and WOW! Piston top is really damaged on the upper piston with scoring on the cylinder walls. Lower piston also has some dings so evidently rings blew out the port after doing the damage. Looks like repower time to my dismay. Anyone out there feel that it is worth rebuilding a sixteen year old motor? If so, what are general costs? Have to make a decision. Thank you all for the replies and advice, Chris
Bigshot	posted 07-31-2003 10:06 AM ET (US) Looking at $1500-2500 depending on who and "what" they rebuild. I personally do not care for rebuilds when you can get a real nice 2000 or 2001 for $4k or less. There is one here for sale delivered to your door for $4000 with all equip.
litnin	posted 07-31-2003 10:56 AM ET (US) Bigshot, give me names and places. I know that Ed's Marine Superstore in Virginia has Johnson 90 2s for 4495.00 without controls. Seems that depending on who you talk to, my existing controls and harness may or may not work. Everyone seems to try and get their hand in your pocket. Telling the truth is a rare commodity out in the business world, it seems. How about the dude in Marketplace selling the DF70's like yours for 5300.00? I need hole shot for pulling kids up on ski's. Thanks for your input. Chris
captbone	posted 07-31-2003 11:31 AM ET (US) Clean out the cylinders and slap it back together and run it until it dies. You can get the end of the summer out of it. Why not, the powerhead needs to be rebuilt anyway? Plus, for the 2 grand you wil drop on that, you may just as well put it towards a new motor. Who knows when the lower unit or something else will go. just my 2 cents.
Bigshot	posted 07-31-2003 11:41 AM ET (US) With damage like that I would not run it. The crank etc are stil good and you can still get $500 or so for it running. Your controls will still work. You need to get a wiring harness adapter for like $35 to connect your old style harness to new. You will also need to get a new tach or add the multifunction guage. New tachs with mulifunction can be had at surplus stores for like $60 or try e-Bay. If you want a good deal on a used or leftover, start calling EVERY marina in your state or nearby atates. I would also try e-Bay, they show up there quite often. If you are not "brand loyal" E-Bay will reveal some god deals. Yes Bayracer is in the ballpark as long as that includes everything but controls. Controls cana also be found on E-Bay or you might be able to use yours. If you find a deal on an Evinrude or Johnson 4 stroke, you can yuse your controls, etc just like with a 2 stroke. The prop you have will also fit both Suzuki and Bombardier/OMC and the Zuki does well with a 17"prop especially if pulling a skier. My boat will pull up a 200lb skier no problem.
litnin	posted 07-31-2003 03:36 PM ET (US) Do the transom holes line on the DF70 Suzuki/Johnson with the old Evinrude V4 holes? I have driven Knothead's Montauk with the Johnson 90 2s and it has great hole shot. Top end for me is pretty unimportant. Wish I could drive one for comparison. Drilling new holes in the transom is a no-no for me. I will be the engine installer on this one to save money. Chris
Bodacious	posted 07-31-2003 06:08 PM ET (US) Hello Folks. I've been lurking here for quite some time and could not resist posting a reply to this thread. Out on boattradeonline. com , under the "motors" heading, there is a dealer in Havelock N.C. that is offering a new 02 Suzuki DF70 for 4995.00. No controls, no prop. It does come with the 6 year warranty. The dealership is Walsh Marine. Good Luck Don
Bigshot	posted 08-01-2003 11:11 AM ET (US) Is that Bayracer? The bolt holes will line up as long as the original engine was not drilled for the blind holes.....then nothing will match. If you can see the lower bolts in the slots on the engine bracket....good. If no nuts are seen, then your best bet is a Manual jackplate for $150 and just drill through the aluminum jackplate and keep the old holes. I had to do his on my Newtauk being the dealer used the blind holes.....took 15 minutes to drill the plate.
nevada	posted 08-01-2003 12:19 PM ET (US) Bigshot, Yes it is bayracer. I found him on E-bay. Joe
litnin	posted 08-01-2003 02:06 PM ET (US) Must make a decision. It will either be the Johnson 90 2s because of worry about hole shot for pulling up a skier OR the DF70 from Bayracer, mostly because of the six year warranty. Difference will be basically 1000k more for the DF70 because of higher initial cost plus having to pay NC sales tax. Any opinions?
Bigshot	posted 08-01-2003 02:15 PM ET (US) Unless you have some "husky" children, get the DF70. You will love it and in about 600 hours make up the price difference in fuel savings. I would not trade my 70 for any 2 stroke. You can still use your old prop on the zuki, just have to shim it some. The sales tax is almost same as shipping so look at it that way.....6 in one hand....:) PS is he selling it for $4995 or $5300?
litnin	posted 08-01-2003 05:05 PM ET (US) Evidently 4995.00 for the boattrader.com crowd and 5300.00 for the Whaler crowd. Sounds like discrimination. Anyway, maybe I misunderstood your earlier post. If I buy a Johnson 90 2s, and my existing engine uses the blind lower holes, will it not line up? Please advise. Pressure is on. Chris
Gene in NC	posted 08-04-2003 07:04 AM ET (US) My '87 sounds identical to yours, both configuration and performance. Power head reportedly rebuilt before I bot it. We fished the Crocker tournament 7/26, ran it in FL this winter and my son is running it all over the Wilmington area right now. Need to do compression check and will report. Forget the 70 go with a 90. Kids grow. Kids want to invite friends. Kids want to ski double. Ran a '66 Johnson 100 on Sakonnet for 30 years. Jerked skiers out of the water. Set engine angle down to lift the stern not the bow. Pulled double slalom skiers w/o prob including spectators in the boat. With engine tucked in ran 36 at 5500. Plenty fast. Just left it that way. No pt in the old days. Run the engine on your vacation. Damage already done. Even if it blows completely you will have a complete set of spares for the replacement. Plenty time to rebuild yourself or find another. That engine common as dirt. If you can keep a MG going your can rebuild that power head. A friend did his. If you like I will get his report on out of pocket cost.
Bigshot	posted 08-04-2003 10:09 AM ET (US) Gene my point exactly....your old 100 did 36 and you loved it. The 70 will do 39, so why go with a 90 and do 42 and burn twice the gas? The Johnson will use your controls, prop, key, etc. You just have to buy a $35 wiring harness adapter and a systems check guage.....period. Try eds on that engine. I heard the $5300 gets it installed, if so not a bad gig.
litnin	posted 08-04-2003 10:23 AM ET (US) Bum at almost local dealer said that nothing I have will work with the new motor and that even my oil tank would need replacing. If I told my customers anything other than the truth, I wouldn't expect to have my customers very long. Thanks for the info. Big's, if I decide to buy the 90 2s, is an extended warranty a good thing to consider. Trust your judgement. Chris Thanks to Gene also.
Bigshot	posted 08-04-2003 11:31 AM ET (US) I thought they were offering 5 year with Bombardier. IF not it REALLY depends on price. I personally think they are a waste of money but if a 5 year is $600 then.....