Yamaha F150 issues

fishnwhenIcan

fishnwhenIcan

Well-Known Member
Came back from Sandheads last Sunday and the engine ran really rough not able to get over 4200 rpm. I went to the marina this afternoon looking to find the issue. Had the throttle up around 1800 rpm and started pulling spark plug leads one at a time. Number 1 and # 4 pulled the engine down significantly while 2 and 3 made very little difference. Two and three share a coil so I swapped the two coils to see if there was any difference and non whatsoever.

Any ideas guys. The engine has 550 hours on it and is a 2004. Would it be time for injectors. The engine has always run like a top. I think it was starting to run a little rough going back a couple of weeks after I nailed a log. I was thinking it was a dinged prop and changed it out last Saturday. I guess the timing was coincidental. Might pull it out of the water tomorrow. Any recommendations on a good marine mechanic in Langley?
 
It's wierd because it seemed to start with that hit and gradually get worse. But what I don't understand is why two and three cylinder are down. It's running rough not just down evenly on power. That would have had me looking more at fuel filters, which I changed anyways as well as plugs which looked fine.
 
I was by reaction back in neutral before the hull or the leg hit the log but I did hit it hard. I can't see any damage to the leg and looking over the prop I removed, it looks fine. I might see more once it's out. So I don't know if they are connected or just something.
 
I have a compression tester I never really thought to take with me. But I did not know I was down on any cylinders. I've been doing some reading and guys sure seem to point to fuel issues on these engines. I saw one mention of each injector having a separate filter. Anybody known if that's true?
 
I'm wondering if those two injectors are needing a good cleaning. Maybe run some concentrated seafoam in an auction tank through first before seeing a mechanic.
 
You could be right on the injectors it's kind of what's left. I was hoping to fix her while she was still in the water to test. But you can hear this at an idle so I can pull it and still be able to tell when fixed.
 
My encounter with a log, left me a cracked camshaft that resulted in a rough running engine. It still ran but at reduced rpm and rough. Good luck !
 
fishnwhenIcan said:
I have a compression tester I never really thought to take with me. But I did not know I was down on any cylinders. I've been doing some reading and guys sure seem to point to fuel issues on these engines. I saw one mention of each injector having a separate filter. Anybody known if that's true?
Click to expand...
The injectors each have their own inlet screen, but no paper filters, there are however 5 if memory serves right different fuel filters on that engine, there is also a tank that needs cleaning, the intake plenum has to be removed to do it, I have had mine apart it's easy to do just time consuming and needs to be out of the water when you do it.
It's all posted on THT
 
I think all the VST? Got done when the balancer was updated. Thanks for bringing that to my attention a while back by the way. All those parts I got from Andy at SIM? Thanks for that reccomendation too. Unless we missed something but is there anything that would only affect some of the cylinders not all as far as filters go.

The more I think of when I hit the log the more I think this is somehow related. I was concerned I'd done some damage af the time as something felt off just a bit, a vibration I put down to a prop. It might have been a slight miss that got worse. I'm going to pull it today and have a better look. I'm keeping my fingers crossed it's not something serious.
 
The injectors come out real easy, I took mine to the guys in port kells and had them serviced, made a difference in the idle for sure
 
When you hit the log did the motor flip up hard enough to
Maybe a pinched wire or two in the loom coming in?
Also the comp test is prob a good idea,
And how do the spark plugs look?
See if the 2 problem cylinders are producing any abnormal signs on the plugs, be it oily, sooty, white or just washed off
 
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I just got the boat home. Seems to be getting even worse. I limped her over to McDonald Beach not wanting to do anymore damage. Tim, when I hit the log I was doing about 30 mph and saw it like 30' in front of me. Too late to swerve but my survival reaction had me pull back into nuetral. The motor did not kickup. I checked and changed the plugs yesterday but the others looked fine. I did not have much time on the motor running bad so I'm not sure how bad the plugs would look.

I need to wash the Fraser River off of her and try to check the compression. I inspected the leg at the ramp and did not see any damage.
 
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As indicated above my thr first thing i would do is a compression check and make sure they are in specs.
 
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