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Author Topic:   NAUSET: Changing to 25-inch Shaft

BigDaddyWhaler posted 10-29-2007 11:16 PM ET (US)
I am the proud owner of a used 1999 115 hp Evinrude Ficht 25-inch shaft outboard. I just bought the outboard this past Saturday. I have gone 4 years with my whaler sitting in my garage waiting for a motor. The old motor is a 70 hp evinrude 20 inch shaft. Will I run into problems running the longer shaft? Do I have to raise the motor using jack plates? I measured the transom and know that I have 1 to 2 inches of play in shafts length. The actual transom measurment is 23 inches so a 25 inch shaft in theory will work. Any help will be appreciated. Also I have to add the oil resvoir for oil injection system help with this will be appreicated. Thanks, Quintin
Tom W Clark posted 10-30-2007 09:35 AM ET (US)
No, a 25" shaft length motor will not work on your Nauset unless you use a jack plate to raise it 5 inches or more.
You do not measure a transom height by running a tape along it, you measure the vertical distance from the keel to the top of the transom. Because the Whaler transom slopes backwards so much, the difference accounts for the 23 inches you measured.
Think of a right triangle. The transom height is the altitude of the triangle, not the hypotenuse.
Furthermore, the Nauset will perform better if the motor is mounted up a bit. With a 20" shaft length motor, raising the motor one or two bolt holes (3/4" to 1-1/2" above the top of the transom) will yield better performance. With a 25" shaft length motor this is even more difficult to achieve.
I would wait and find a 20" motor that fits correctly.
blkmtrfan posted 10-30-2007 12:18 PM ET (US)

quote:
I would wait and find a 20" motor that fits correctly
Or modify the motor you just bought to a 20"....
BigDaddyWhaler posted 10-30-2007 06:56 PM ET (US)
I paid little for the motor--$1,000. I'm almost stuck having to [use it]. It is too expensive to convert the motor to a 20-inch shaft. I've looked at fixed jack plates and adjustable jack plates by [T&H Marine]. Info [about jack plates] would help.
jimh posted 10-30-2007 08:21 PM ET (US)
You can find information about T&H Marine jack plates at the T&H Marine website.
http://www.thmarine.com/category.cfm?CID=43&CHID=1
Tom W Clark posted 10-31-2007 08:28 AM ET (US)
blkmtrfan,
You can turn a 20" shaft motor into a 25" shaft motor by adding a 5" shaft extension kit, but you cannot change a 25" shaft motor into a 20" shaft motor unless it has a shaft extension kit to remove.
The easiest and least expensive way to install a 25" shaft motor on a 20" transom would be to use the CMC 5" extension, part #50012.
Tohsgib posted 10-31-2007 09:54 AM ET (US)
Jack plate will work just fine, good steal on the negine as well. Post some performance numbers when you get dialed in. Like Tom said raise it up 1-2" above the keel so about 6.5" total. Yes the plate might only raise it 5" but you can raise the engine on the plate as well.
blkmtrfan posted 10-31-2007 11:02 AM ET (US)

Tom you can make any motor into any shaft length (with enough fab skills) if you really want to, LOL
Seriously though, the high perf guys make these kind of modifications all the time. In this case he got the motor cheap, as I figured, which is good.
Now just locate a blown 20" ficht and swap your good parts on. You will have several hundered dollars into the jack plate rigging materials plus your labor anyway, why not just do it right?
Just my opinion, but I really think using a jack plate to "band-aid" the wrong shaft length is a bad idea. Raising the center of gravity in a low profile skiff does not help performance or improve stability. Plus no matter how good you do it, it will always look like you have the wrong motor on your boat. Once again, just my $0.02
Tohsgib posted 10-31-2007 11:34 AM ET (US)
It is only 5" for God's sake...how is that going to effect anything?
blkmtrfan posted 10-31-2007 03:18 PM ET (US)

Like is said, it is my opinion :)
I wouldn't rig that boat like that, BigDaddyWhaler can do what ever he wishes as it is his boat, but he was asking for opinions...
Personally, I will not ever (I know you aren't supposed to say "not ever" or "never", LOL) rig my 13' with anything but a proper 15" motor, even if I have to cut a 20" down to do so :)
BigDaddyWhaler posted 10-31-2007 10:48 PM ET (US)
Some of you guys might not know this but this boat has been sitting in my garage waiting for a motor. I've had two kids, bought my wife a commuter car, and fixed everything else in my house. Sure I've seen lots of motors cheap but not worth the money. I wouldn't take any of those motors out in the ocean. I finally found one at my price and reliable enough to take out salmon fishing and albacore fishing. This time I'm doing something for me. Any way after all the discussion. I hang the motor. go out sturgeon, salmon, albacore, anything to do with the boat fix, have the motor for sale at the same time. And hopefully that puts me over the brand new motor amount fund. Happy Whalering
Tom W Clark posted 10-31-2007 10:53 PM ET (US)
Quintin,
Go for it. Here is a CMC 50012 for only $109:
http://www.magemarine.com/cmc/transom-jack-plate/
Tohsgib posted 10-31-2007 11:14 PM ET (US)
yeah!
blkmtrfan posted 11-01-2007 10:10 AM ET (US)
Just go boating!
Sounds like a great plan
I have to admit there is no way I could go 4 years without boating.....
Plotman posted 11-02-2007 10:36 AM ET (US)
I have 25 inch motors on a transom in a situation that calls for 20 inch motors. They are on static Jack Plates. Other than an extra 20 lbs or so per engine, there is no downside that I can see.
Binkie posted 11-02-2007 10:49 AM ET (US)
http://www.dillon-racing.com/
Home Made jack plate free plans. Should be good for 90hp. Use heavier aluminum.
rich
Binkie posted 11-02-2007 11:09 AM ET (US)
http://www.dillon-racing.com/
BigDaddyWhaler posted 11-17-2007 08:48 PM ET (US)
Guess what guys. The motor is hung. The brackets are installed. New wiring harness, oil resvoir, new control cables, alot of things got changed for going to longer shaft. I havent hit the water yet hopefully next week. The San Francisco Bay is closed to all fishing right now because of the oil spill.
Binkie posted 11-17-2007 10:28 PM ET (US)
Would you post some pics of the install?
Rich
BigDaddyWhaler posted 11-19-2007 10:37 PM ET (US)
I'll post some pics as soon as possible. I think this was best solution for my situation. I would like to give a shout out to Brian of the Outboard Motor Shop in Oakland. They were so helpful with the new harness, control cables, prop, they have been selling whalers for as long as I remember. I'm 31. John from Belmont Boat Service was extremely helpfull in selecting the proper prop. Not to mention the people at continuous wave. I've waiting sometime to get her back on the water and I'm just waiting for a free weekend. I going to put some hours on her before the superbowl sturgeon derby. Pics soon to follow. Tight lines.
JayR posted 11-20-2007 06:31 AM ET (US)
Can't wait to see it!
I'm thinking of doing the opposite. A 20" shaft on a 25" transom and lowering the motor 3".
It's always nice to see modifications and get performance results. It can help others or save some from a lot of unnecessary work.
Get those pics up as soon as you can.

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Author	Topic: NAUSET: Changing to 25-inch Shaft
BigDaddyWhaler	posted 10-29-2007 11:16 PM ET (US) I am the proud owner of a used 1999 115 hp Evinrude Ficht 25-inch shaft outboard. I just bought the outboard this past Saturday. I have gone 4 years with my whaler sitting in my garage waiting for a motor. The old motor is a 70 hp evinrude 20 inch shaft. Will I run into problems running the longer shaft? Do I have to raise the motor using jack plates? I measured the transom and know that I have 1 to 2 inches of play in shafts length. The actual transom measurment is 23 inches so a 25 inch shaft in theory will work. Any help will be appreciated. Also I have to add the oil resvoir for oil injection system help with this will be appreicated. Thanks, Quintin
Tom W Clark	posted 10-30-2007 09:35 AM ET (US) No, a 25" shaft length motor will not work on your Nauset unless you use a jack plate to raise it 5 inches or more. You do not measure a transom height by running a tape along it, you measure the vertical distance from the keel to the top of the transom. Because the Whaler transom slopes backwards so much, the difference accounts for the 23 inches you measured. Think of a right triangle. The transom height is the altitude of the triangle, not the hypotenuse. Furthermore, the Nauset will perform better if the motor is mounted up a bit. With a 20" shaft length motor, raising the motor one or two bolt holes (3/4" to 1-1/2" above the top of the transom) will yield better performance. With a 25" shaft length motor this is even more difficult to achieve. I would wait and find a 20" motor that fits correctly.
blkmtrfan	posted 10-30-2007 12:18 PM ET (US) quote: I would wait and find a 20" motor that fits correctly Or modify the motor you just bought to a 20"....
BigDaddyWhaler	posted 10-30-2007 06:56 PM ET (US) I paid little for the motor--$1,000. I'm almost stuck having to [use it]. It is too expensive to convert the motor to a 20-inch shaft. I've looked at fixed jack plates and adjustable jack plates by [T&H Marine]. Info [about jack plates] would help.
jimh	posted 10-30-2007 08:21 PM ET (US) You can find information about T&H Marine jack plates at the T&H Marine website. http://www.thmarine.com/category.cfm?CID=43&CHID=1
Tom W Clark	posted 10-31-2007 08:28 AM ET (US) blkmtrfan, You can turn a 20" shaft motor into a 25" shaft motor by adding a 5" shaft extension kit, but you cannot change a 25" shaft motor into a 20" shaft motor unless it has a shaft extension kit to remove. The easiest and least expensive way to install a 25" shaft motor on a 20" transom would be to use the CMC 5" extension, part #50012.
Tohsgib	posted 10-31-2007 09:54 AM ET (US) Jack plate will work just fine, good steal on the negine as well. Post some performance numbers when you get dialed in. Like Tom said raise it up 1-2" above the keel so about 6.5" total. Yes the plate might only raise it 5" but you can raise the engine on the plate as well.
blkmtrfan	posted 10-31-2007 11:02 AM ET (US) Tom you can make any motor into any shaft length (with enough fab skills) if you really want to, LOL Seriously though, the high perf guys make these kind of modifications all the time. In this case he got the motor cheap, as I figured, which is good. Now just locate a blown 20" ficht and swap your good parts on. You will have several hundered dollars into the jack plate rigging materials plus your labor anyway, why not just do it right? Just my opinion, but I really think using a jack plate to "band-aid" the wrong shaft length is a bad idea. Raising the center of gravity in a low profile skiff does not help performance or improve stability. Plus no matter how good you do it, it will always look like you have the wrong motor on your boat. Once again, just my $0.02
Tohsgib	posted 10-31-2007 11:34 AM ET (US) It is only 5" for God's sake...how is that going to effect anything?
blkmtrfan	posted 10-31-2007 03:18 PM ET (US) Like is said, it is my opinion :) I wouldn't rig that boat like that, BigDaddyWhaler can do what ever he wishes as it is his boat, but he was asking for opinions... Personally, I will not ever (I know you aren't supposed to say "not ever" or "never", LOL) rig my 13' with anything but a proper 15" motor, even if I have to cut a 20" down to do so :)
BigDaddyWhaler	posted 10-31-2007 10:48 PM ET (US) Some of you guys might not know this but this boat has been sitting in my garage waiting for a motor. I've had two kids, bought my wife a commuter car, and fixed everything else in my house. Sure I've seen lots of motors cheap but not worth the money. I wouldn't take any of those motors out in the ocean. I finally found one at my price and reliable enough to take out salmon fishing and albacore fishing. This time I'm doing something for me. Any way after all the discussion. I hang the motor. go out sturgeon, salmon, albacore, anything to do with the boat fix, have the motor for sale at the same time. And hopefully that puts me over the brand new motor amount fund. Happy Whalering
Tom W Clark	posted 10-31-2007 10:53 PM ET (US) Quintin, Go for it. Here is a CMC 50012 for only $109: http://www.magemarine.com/cmc/transom-jack-plate/
Tohsgib	posted 10-31-2007 11:14 PM ET (US) yeah!
blkmtrfan	posted 11-01-2007 10:10 AM ET (US) Just go boating! Sounds like a great plan I have to admit there is no way I could go 4 years without boating.....
Plotman	posted 11-02-2007 10:36 AM ET (US) I have 25 inch motors on a transom in a situation that calls for 20 inch motors. They are on static Jack Plates. Other than an extra 20 lbs or so per engine, there is no downside that I can see.
Binkie	posted 11-02-2007 10:49 AM ET (US) http://www.dillon-racing.com/ Home Made jack plate free plans. Should be good for 90hp. Use heavier aluminum. rich
Binkie	posted 11-02-2007 11:09 AM ET (US) http://www.dillon-racing.com/
BigDaddyWhaler	posted 11-17-2007 08:48 PM ET (US) Guess what guys. The motor is hung. The brackets are installed. New wiring harness, oil resvoir, new control cables, alot of things got changed for going to longer shaft. I havent hit the water yet hopefully next week. The San Francisco Bay is closed to all fishing right now because of the oil spill.
Binkie	posted 11-17-2007 10:28 PM ET (US) Would you post some pics of the install? Rich
BigDaddyWhaler	posted 11-19-2007 10:37 PM ET (US) I'll post some pics as soon as possible. I think this was best solution for my situation. I would like to give a shout out to Brian of the Outboard Motor Shop in Oakland. They were so helpful with the new harness, control cables, prop, they have been selling whalers for as long as I remember. I'm 31. John from Belmont Boat Service was extremely helpfull in selecting the proper prop. Not to mention the people at continuous wave. I've waiting sometime to get her back on the water and I'm just waiting for a free weekend. I going to put some hours on her before the superbowl sturgeon derby. Pics soon to follow. Tight lines.
JayR	posted 11-20-2007 06:31 AM ET (US) Can't wait to see it! I'm thinking of doing the opposite. A 20" shaft on a 25" transom and lowering the motor 3". It's always nice to see modifications and get performance results. It can help others or save some from a lot of unnecessary work. Get those pics up as soon as you can.