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Author Topic:   4stroke maintenance
dirk posted 06-28-2005 04:25 PM ET (US)   Profile for dirk  
I have a new BW Montauk 170 with Mercury 4stroke 90 HP.My dealer advises to change oil and inspect the engine after 20 hours use. I read on this forum that the opininons concerning this subject are divided. I think I will use the boat 50-75 hours before winter. Can I wait till winter ?
bsmotril posted 06-28-2005 04:28 PM ET (US)     Profile for bsmotril  Send Email to bsmotril     
Sure you can. But first check with the dealer to determine if the 20 hour checkup is a condition to keep the warranty valid.
Buckda posted 06-28-2005 05:20 PM ET (US)     Profile for Buckda  Send Email to Buckda     
I had an interesting conversation with the owner of a fishing camp in Canada last week. We were sitting along the dock, getting ready to go fishing and struck up one of those easy conversations that just sort of happen when the day is hot and no one really is in any hurry to go catch fish. I asked him why he went with a purchase of Yamaha 20 HP 2-strokes instead of 4-Stroke outboards for his boats. After all, I reasoned, he had to FLY in all gasoline and oil that was needed for the 25 engines he was running at the camp, in addition to everything else the camp needed to operate.

His response: Too much maintenance. I blinked hard and asked him what he meant.

Turns out that by his best estimate, the motors see about 80 or so hours of operation a week, on average, meaning about 800 hours a season. He asked the rhetorical question about when he was going to have the time to change the oil in all of those motors at the recommended interval?

Good thoughts.

Anyway...there IS a camp on that lake operating 4-stroke Honda 9.9's. I dont' know how often they change the oil, but they've been running for 4 years on a similar schedule, and I seriously doubt that they see an oil change other than in the fall or spring either right after or right before another season.

My guess is that you can make it, no problem...the concern, as stated above is about the warranty.

17 bodega posted 06-28-2005 08:11 PM ET (US)     Profile for 17 bodega  Send Email to 17 bodega     
The newer motors are not tough to work on. Many don't like to change their plan if it ain't broken. I can change my own oil in my 4 stroke and do the plugs and grease moving parts. The only dealer level service is the valve adjustment and carb sync if not EFI. I think folks will get used to the idea of changing oil soon. I've been watching my mechanics do work on my motor and all parts were easy to access. Very cool technology. I'm sure the new 2 strokes are nice too.

17 bodega posted 06-28-2005 08:13 PM ET (US)     Profile for 17 bodega  Send Email to 17 bodega     
Oh yeah, go ahead and do the service for 20 hours. You should have a conversation with your dealer about break in procedures. That motor is too expensive to mess around with saving a few bucks on a service. Save your money elsewhere.

My .02

bigjohn1 posted 06-29-2005 07:58 AM ET (US)     Profile for bigjohn1  Send Email to bigjohn1     
Dirk, do yourself a favor and just change the oil (or have the dealer do it) at 20 hours. Regardless of the opinions expressed here, none of us will bear the brunt of the problem if, for some weird reason, you have an oil-related problem and the dealer plays hardball and decides not to honor your warranty.

In theory anyways, a brand new 4-cycle engine will develop more foreign material in the oil for the first few hours as the new internal engine parts are broken in. Believe this if you want or choose not to, its up to you. Personally, I believe it depends on if the engine was "broken in" by the manufacturer prior to it leaving the assembly plant....and I do not know if Merc does this or not. Since the factory recommends an initial 20-hour oil change, I am betting that Merc does not "break in" their outboards at the factory.

bigjohn1 posted 06-29-2005 08:29 AM ET (US)     Profile for bigjohn1  Send Email to bigjohn1     
Dave, interesting discussion you recounted with the fishing camp owner. One observation though, he is running a "fleet" of vehicles as a business complete with the various business tax write-offs. This might well affect his decision to be as meticulous on maintenance as he would be if it were his personal marine outboard. I have no knowledge of the Canadian tax system but its just a thought.
Moe posted 06-29-2005 09:06 AM ET (US)     Profile for Moe  Send Email to Moe     
I scoured the owner's manual and factory service manual for our 60HP BigFoot EFI, looking for a 20 hour service and couldn't find one. Nevertheless, I change the motor oil and filter, and lower unit oil at about 20 hours because of the shearing the oil experiences with newly machined parts such as piston rings before they seat. The oil filter should catch the metal particles that result from break-in.

Keep in mind that full synthetic oil is good for 25,000 miles in automobile engines, which would probably translate to somewhere around 400 hours with an outboard... for those who would put that many on in a season. I'd still change it annually to get rid of the acids that build up in it.


elaelap posted 06-29-2005 12:22 PM ET (US)     Profile for elaelap  Send Email to elaelap     
If I remember correctly, my Yamaha 115 EFI manual called for an early oil change after the ten-hour 'break-in' period. I let the dealership do it just that once along with a post break-in 'tune-up.' Now I change my oil at +/-70 hour intervals, which is fairly often since I just yesterday hit hour 455 on my motor which I bought new in late March of last year.

Moe--I wasn't aware that synthetic oil is supposedly good for such long periods of time. Do you know of any information about the use of such oil in four stroke outboards? The funny thing is, I'm not sure I'd go with it even considering the convenience. It's helpful to my mechanically disinclined psyche to force myself, every three weeks or so, to pull the cover off my motor and at least visually check it out while changing oil. I also use that time to tighten nuts if needed, dab grease where necessary, tighten my boat's rails, and in general give things a good once-over within my limited capabilities. I also let the shop check things out with a 200 hour 'tune-up' twice a year.


Buckda posted 06-29-2005 12:27 PM ET (US)     Profile for Buckda  Send Email to Buckda     
John -

Of course, you are right...and his plans include keeping the motors for only 5 years and then trading them in for new ones(these are not leased motors), so it's not like a recreational motor you expect to keep for 20 years or so...but they're seeing a TON more use than the average boater......other comment he made was that his Yamaha rep promised him that their small outboards (20 hp) would meet the emissions requirements in three years when he has to buy again. I'm wondering if there won't be a fleet provision for "dirtier" engines, much the same as the diesel trucks on our highways get away with less stringent emissions....

I also don't know about the canadian tax implications on his business for write-offs...but I would assume that they are a similar system to the US with slight hint of European flavor thrown in....

My point was that those Hondas seem to be running just fine after 4 years, and I'm relatively confident that they don't get the "recommended" changes, rather they get their oil changed when it is convenient for the owners...meaning at the beginning or end of an 800 hour season, and that is probably it. These guys don't have a ton of extra engines or boats laying around to run standby while they rotate stock for maintenance. The boats are "unclaimed" from about 7 PM on Fridays when the boats are cleaned and prepped for the next group, and are "claimed" starting about 7:15 AM on Saturday when the next group of fishermen step off the float plane. Extra boats or motors are inefficient for the camp operation, especially when they either would have to be flown in strapped under the plane, or hauled in on sled in the winter, and the camps are operating on thin margins as it is.

Final comment that we all probably know instinctively, but I can't really prove, is that the smaller engines seem to be made to run at WOT all the time. We have a Scott-Attwater 10 HP motor from the 50's that is still running strong. The bigger motors are stressed harder (pushing heavier boats through heavier seas) and don't seem to last as it's not really an apples to apples comparison.

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