Pontoon Boat & Deck Boat Forum

The marina said they fixed my oil leak.

Went out to the boat and I've got a motor well full of oil Or at least oily water.

So I called them and he said that hopefully it's just leftover. otherwise the Yamaha guy he talked to said it would be the lower pistons (?) and it would require a motor rebuild to fix.

I am both motor ignorant and time short so I'd have to pay someone to do this. Any idea of what it should cost (That is, how painful is it)

It doesn't take a whole lot of oil, to look like a lot when its suspended on water. I would fire it up on muffs with the the cowl off and run it, looking for a leak. I sure can't see a piston job even being recommended without a visual and compression test being done. Sounds kinda like someone is talking before thinking, John! I wouldn't submit to a repair without a thorough look over being done.
Good luck with her Buddy! Lets keep that Manitou on the water! You have a very nice boat that will last you for years! And that motor is bulletproof, get her checked out... I hope you are ok and it is just residual oil from the repair.

Want to know what kind of shape your pistons and bore are in? Have a compression test or better yet cylinder leak down test done; I'd shy away fro any shop that gives recommendations without doing either...

Thought I'd stop in and let everyone know how this ended up.

If you all remember from my prior post they replaced the check valve on the No 1 cylinder and we were waiting to see if that solved it.

It didn't. Still had oil leaking from the number one cylinder. The marina guys were tearing their hair out.


They ended up spending about 10 hours on the phone with Yamaha stepping through the whole oil system. They finally came to the check valves (check valves????) and found the problem.

Apparently the Yamaha HPDI VMAX motors have 2 check valves per cylinder!!. They replaced the top one (which is easily seen) but never saw the lower one.

Got that valve fixed and the problem went away.

The bad news is that I lost just about the whole summer. The good news is that the marina is eating most of the effort spent on the repair. In fact, I called them just the other day because I've not been billed on it and the manager said he didn't even know what to charge me. He told the guys to just write it off. I still expect a bill, just not nearly as bad as I had feared.

I still have to get the ACR fixed but I'll deal with that in springtime

Next summer I should be in great shape to get on the water!

That's good news John! and good service!

Great! Glad to hear they got it fixed and we learned something new about the V max's, too! Hope next summer you can double your time on the water!

My old boat had a Yamaha 115 hp 2 stroke--one of the first imported into the U.S. It was a great performing engine. The only problem I had in 28 years use was the oil injection, and it ran me crazy for 3-4 years. Come to find out that Yamaha's oil injection system was 1/2 mechanical and 1/2 electronic. I installed those tiny check valves as trial and error in the oil injection lines. My problem was a bad electronic module that controlled the oil pumps in the external tank and the floats on the small oil tank on the powerhead. $241 and it was fixed.

But if anyone ever has a 2 stroke Yamaha that needs rebuilding, the best guy for the job is Carson Marine in South Florida. He has a full in house machine shop, and is as good as there is on 2 strokes. A 6 cylinder 2 stroke Yamaha rebuild is in the $4K range. the cost of outboard parts, including bearings and pistons, are unbelievable. Sometimes it's just easier to go to a more modern engine when repowering.