Yamaha F-225 Fuel problem please help!

I have been referred to Rodbolt from another user on another forum. He says Rodbolt is very knowledgeable on the F-225.

This is what I posted on another site.

I know some dealer or boat owner has had this problem or heard of one like it before I'm in dire need of assistance and ideas before I just give up.

last October my 2004 F-225 lost RMP while leaving the dock. When I advanced power lever to 2100 RPM it would just bog down. Called a mechanic and ran the boat at the dock. Put it under load and it worked fine. Left the dock and got 6000 RPM for almost an hour. Then RPM dropped off and and boat would barely run above idle. 1/2 hour later boat ran fine. When we put it on the trailer it would not get above 1500 RPM.

Mechanic said VST screen was probably clogged so we removed it. it was full of white chalky stuff. Cleaned the VST screen and boat ran great for 14 hours. Same problem returned but have more depth now. When accelerating, sometimes at a RPM range near 2000, or 3000 or 5000 the boat suddenly bogs down. If you continue to push up the throttle RPM decreases but when you pull the throttle back, at some point RPM increases again. When it happens engine does run rougher than normal but one minute later smooth as can be at 6000 rpm. Put a fuel gauge on the rail pressure at 42 lbs then suddenly drops to 20 then boat runs real rough at 10 shuts down. Ran on an external tank same problem. Have done diagnostic several times no problems show up.

Took the VST screen off again and found it full of white powder. Found the bottom of the VST tank corroded. replaced the VST tank. Same problem. Took all fuel (clean) out of the tank. Replaced pick up and fuel tank indicator. Replaced all filters on the engine several times, replaced racor several times. Changed the ball, All has had no effect on the problem. last week decided to change the HP fuel pump. Pump looked good, clean could not get any deposits out of it. Finally ran the boat today and the problem is the same. Seems to be totally starving for fuel (sometimes). Initially would not get above 1500 rpm then 2200, then 3100 then suddenly it accelerated normally and got 5700 RPM and ran smooth. As soon as I pulled it back it would not get above 2000 again for the rest of the trial.

The real symptoms, run the motor in a bag. looks and runs smooth. Put it under load and it seems at some point (low RPM) to start running a little rough. Advance the throttle and everything feels normal until a certain RPM and then RPM decreases rapidly and engine starves for fuel. Bogs sometimes backfires or just sputters. Pull throttle back and at some point RPM increases to a point.

I guess in re-thinking the problem, most probably the severely clogged VST screen was probably never the problem or it was just part of a problem. The only thing left is the fuel regulator and I'm not sure if this would have these symptoms or not. I think having the pressure drop on the rail eliminates injectors, injector pumps and the like. I think. Of course today it ran at almost full power without skipping a beat for several minutes.

I now have been given the idea to pinch the return line when it happens to see if the regulator is porting too much fuel. I'll try that next time I can out the boat in the water.

I think I am also faced with an entire different problem with the exhaust corrosion. Can you guys take a look at my video and tell me what you think?
exhaust 006 - YouTube

Thanks
Rick http://forums.iboats.com/images/icons/icon8.png
bigfish@hawaii.rr.com

Re: Yamaha F-225 Fuel problem please help!

Just to let you know Rodbolt does not post here anymore, been some time since he has.

If you are still loosing fuel pressure you need to address restrictions would be my thoughts, but does not look like you have tested pressure lately.
Also if the screens and filters were having problems , your injectors need to be cleaned and flow tested also.

Hope you had tank cleaned not just drained, that white powder is probably in all lines too

Re: Yamaha F-225 Fuel problem please help!

99yam40 said:

Just to let you know Rodbolt does not post here anymore, been some time since he has.

If you are still loosing fuel pressure you need to address restrictions would be my thoughts, but does not look like you have tested pressure lately.
Also if the screens and filters were having problems , your injectors need to be cleaned and flow tested also.

Hope you had tank cleaned not just drained, that white powder is probably in all lines too

Click to expand...

Thanks do you know if there is a means to contact Rodbolt by phone or email or better yet is it a person or a dealer or both?
We actually have tested the pressure at the rail 3 times and it is always the same. Pressure drops and engine runs rough.
My question is (like you say) wouldn't that mean that there is some type of intermittent problem prior to the HP pump? So if I eliminate the boat (run external tank) and it remains the same, the problem should be fuel or electrical right there between the first filter and the rail. I will check and clean the injectors anyway but really want to focus on fixing the problem.

We emptied and cleaned the tank no white residue found. never have had i speck of residue in any filter that we have seen. always spotless. Only the VST screen twice and it looks like the VST tank corrosion was the problem.

Thanks,
Rick

Re: Yamaha F-225 Fuel problem please help!

Have you checked the float valve in the VST? I had one the other day that had clogged up and restricted the fuel going into the tank.

Re: Yamaha F-225 Fuel problem please help!

pm sent on Rodbolt


Might want to monitor pressue going into VST and rail pressure at same time to see if both are dropping