F 115 Yamaha 4-stroke issues

[cjac]

Hey all,

Any ideas? My F115 Yamaha 4-stroke idles fine, but when I kick it down it goes OK but you'll hear and notice a RPM drop around 4500. It just won't kick into the powerband of RPMs. I get 38ish mph (s/b 43mph), but it just won't kick into the top end. Best I can get while goosing the trim up is around 5-5200k.

I changed plugs, looked around and didn't see any signs of anything leaking and the throttle linkage looked fine. I added a can of Sea Foam, but to no avail, and I did run it enough to get that moving thru the motor. It's almost like a cylendar is missing. Thoughts....or is it off to the shop?

Thanks.....

[Esox_Magnum]

My buddy had an issue with his 80 Yammi earlier this year similar to yours I think it was a sensor for fuel or something that was bad. His is an 02 4 stroke tiller. I tried calling him to ask but most likley hes out on the water already for the evening. If he calls back I'll let you know, or maybe Matt will see this and recall what the problem was.

[cjac]

Thanks for the assist!

It sounds and "feels" fuel-related/sensor related. I appreciate the call to your buddy!

[Esox_Magnum]

Must be something with you big city boys and your Yammies LOL. No call back yet he may be up to V this weekend and has crappy reception up there.

[Esox_Magnum]

My bad it was a prop issue. Are you sure everythings good back there? Water pumps working ok to?

[marine_man]

Cjac,

I would pull your plugs and see if one looks different than the other. If so, I'd check to see if you have spark on all cylinders.

marine_man

[srj]

Chris, I had a similar problem a few years ago. Idle was fine but way low on top end--it was running on three. I had a load of very bad gas and an injector was plugged. I added a canister type fuel filter and haven't had a problem since. Have you looked at your filter under the hood?

[cjac]

Thanks guys,

Put the new plugs in last weekend, looked at them again and I couldn't see anything different. Check the air intake, trouble-shot as best I could. So, dropped it off this morning.....here's to an inexpensive bill.

[Northlander]

Did you check your oil level and if you had a hard primer ball?

Oh well if you have it in the shop we will find out in a month or so. LOL. Just yokin ya man. I hope its a quick and semi painless expense.

[cjac]

Well, in and out in a day at $200, not bad.

They did the tank test and ran the diagnostics, turns out it was a clogged injector. I'm guessing a bad batch of gas maybe? Ran fine until my trip to Leech, not the right lake to not have 100% confidence in your motor.

I did the garage stuff, but beyond that I didn't want to mess.

Thanks for the recommendations guys!

[Northlander]

Man that was quick and fairly painless. Could have been a lot worse thats for sure.

[cjac]

Quote:

Man that was quick and fairly painless.

When I bought my rig 5 years ago the post-purchase service from the dealer was something I took into consideration. Service for rigs purchased there jump to the front of the line.

Just a tip and point to consider for those looking to purchase at some point in time.

[Northlander]

Ya thats a good point. Sad point at my place is the Rangers, Tritons etc. usually jump to the front more.

[srj]

Cjac, glad you got fixed for 2 bills. I assume you don't have an inline canister filter as I've not heard of anyone running one having problems. A simple addition and not very costly--way less than a repair. Way back when I worked in the marine world, we installed cannisters on any boat sold with a built-in-tank--some came from the manufacuter already installed.

With the dirtier gas today plus the tiny orrifice on injectors, it's more important now than in the past. I've known quite a few guys with plugging problems in the last few years.

Good luck.