Yamaha F150 Fuel Problem?

catface12 · 14 November 2010, 16:17

I have a Yamaha F150 (4 stroke) 2006 with around 2850hrs and was doing routine maintenance yesterday. Opening the VST on the HP electric fuel pump revealed a lot of small particles in the bottom of the tank (a pile almost 1/2" tall). I checked the filters and all were clean (I actually destructively opened the inline filters to look for dirt). I stripped the LP fuel pumps and there is no sign of any dirt anywhere in the fuel system from the tank right through to the VST. I am therefore puzzled as to where these dirt particles have come from as they would have had to pass the Racor in the boat then the inline filter on the motor before the LP pump, and then two more inline filters before ever getting to the VST. Could this be the electric fuel pump brushes disintegrating?

Tony Hill · 14 November 2010, 17:26

Do you use metal jerry cans to refuel? We experienced similar problems and found that the lining of the fuel cans was disintegrating and bypassing the teflon filter of the funnel and both the large yamaha external fuel filter and the inline fuel filter before blocking the filter under the pump in the VST. We added clean the VST to our annual maintenence list

Tony

catface12 · 14 November 2010, 17:34

Hello Tony

Thanks for your comments.

No, actually we only refuel direct from the pump. These engines are on our dive boat and are in almost daily use, clocking up on average more than a thousand hours per year.

I do all my own maintenance (including major engine overhauls) and I have to admit to being totally puzzled. I routinely change the Racor on the boat (at least once a year), also the element in the plastic cannister just inside the cowl and then annually the two other inline filters (the one by the VST and the one by the cannister at the rear of the engine.

Thinking that these filters were not effective, I opened the two inline ones yesterday and there ws not one single particle inside either of htem. This led me to think that maybe the particles were coming from inside the VST itself and the only sensible culprit would seem to be the HP pump. I wondered if the brushes were disintegrating, but thinking about that, it it were true, the particles would have been inside the inlet filter on the bottom of the HP electric pump.

Incidentally, there is no problem with the engine, I am just curious. I suppose I don't like unsolved mysteries of the technical variety!

Tony Hill · 15 November 2010, 08:31

It was just a thought from our own experiences. We found we had trouble at around 1100 hours and the 'problem' jumped all filters. Like you I would not be happy with unsolved problems. I would be interested to know what you find.
We have someone with 2,500 odd hours on a pair of F150's I will try to see if he has had similar. It is useful for us to know

Tony

outboardtech · 21 November 2010, 18:04

hi there , these high pressure pumps and the brushes are bullet proof really in my opinion . i work on these F150 all the time and to be honest the only thing i and we have had issues are is the injectors . if you ever have a rough running issue , lumpy on idle , top of engine shaking a little , this is a sign of a injector on its way . even though you run the diagnostics on it and everything check out OK . I have never had to replace a HP pump on these engines . I had a customer two weeks ago ring me and say his fuel pump dosent turn on with 12v key on and he has a fuel pressure gauge connected and no fuel pressure . please can i order him a pump . the fuse had blown, new fuse and runnin ok. if I had this issue and the fuse kept blowing then i would say brushes shorting out etc . pretty bulletttttttttttttttttttttttttttttttt proof engines . are you doin the cambelt at 300hours . cheers

catface12 · 21 November 2010, 18:34

Thanks for the input.

The engines are running fine. I have the boat out of the water for a major renovation and thought I would take the opportunity to pull the cylinder head to do a de-coke and some other routine maintenance. During this I came accross the muck in the VST. Given that we change all the fuel filters regularly I would not expect to see muck in the VST especially as the engines are in use virtually every day of the year so do not suffer from fuel degrading in the tank. After all, what is the point of all the filters if they allow muck into the VST?

This particular engine has 2894 hours and compressions of 135psi (hot WOT) on all cylinders. There are no problems with it, so by carrying out routine maintenence it stays that way. I change the camshaft drive belt at around 1200 hours (the Yamaha recommendation is 1000 hrs). The engine lives on a diet of Castrol Syntec fully synthetic oil 5W/50.

We run two of these on our smaller dive boat and they do over a 1000 hours each per year. They have proved to be fantastic engines, reliable, fuel efficient and simple to fix. My only "problem" is that the PTT pistons/cylinders don't live long enough, 18 months is about it. I am now on my third set and they are not cheap.

Have just had to put two Mercury Verado 300's on my new dive boat (Yamaha don't make a 300 4T and the 350 V8 is way too heavy and expensive). Let's hope Mercury turn out to ba as good. I am sitting here thinking a better choice might have been Suzuki DF300's, time will tell.

nan-ber · 23 November 2010, 21:01

catfish, i have had ths problem on a 150 also ,on more tha 1 ocassion, that stuff just appears from nowhere, how i found it was t engine started running rough, checked all t usual, eventually removed t faulty injector plugged it 2 a 6 volt battery and blew through in reverse onto tissue paper ther was my red dust , moved onto t vst and got more, seems its a prob on some of t yams, maybe a fuel line rusting internally i dont know

outboardtech · 24 November 2010, 13:49

OH YES Yami now do the LIGHT WEIGHT 300v6 fourstroke.AWESOME engine and lovely.it weighs 258kgs (4169cc) 6 cylinder.DTS shifting and comes with the NEW Instrument monitor