It just quits after prolonged idle....fuel??

Just bought a boat with a pair of 2005 Yam F225 4 strokes. They start instantly and run like string trimmers on meth.

HOWEVER, the port engine just shuts down on its own after prolonged idle. It will stumble a second or two and then just die. If cranked, it will not start. If the primer bulb is vigorously pumped till stiff, the engine starts just fine and all is well, unless you need or want to run at no wake speeds for a while. It will just quit again.

So, I have been running down the creek with the port engine above 1500 rpm and the starboard at the idle detent. It seems as though that amount of power will keep it running.

Sounds to me like there is an air leak between the tank and the engine which is of no consequence when running the engine at high power, but manifests itself under low power settings.

My plan is to start at the tank and tighten every fitting I can find in an attempt to fix this.

Any other suggestions?

Many thanks.

Are engines running off same tank? separate water/ fuel separators on engines? Tighten away on fittings. Are there separate fuel bulbs? Have plugs been pulled and inspected? See if any codes are spitting out,

Same fuel tank. Separate squeeze-bulbs. Separate Racor filters.

I have not touched the plugs and I do not know how to read the codes. Can you enlighten me on that? Will a standard OBD reader work? If not, what do I need?

Sorry, FNG with these engines. Long time inboard guy. Will read read read in an attempt to learn as much as possible.

In addition to checking and tightening everything to eliminate any possibility of an air leak in the fuel line to the engine, check the oil level in the port engine... Is it "making oil" by any chance? Is the oil level above the top range on the dip-stick? If you're "making oil" you could have a mechanical fuel pump diaphram going bad. Simple to check and see if the diaphram is torn, has hole, etc and fix as you can purchase just the diaphram (no need for an entire new fuel pump). Yamaha Service Mafia loves to sell new fuel pumps instead simply replacing the diaphram.

I had my septic system's air pump fail and wouldn't you know it Septic Service Mafia Man wanted to replace the entire pump for $350. I found online the "rebuild kit" with new diaphrams for my pump for $99! Turns out there is a little shear screw in there designed to break when a diaphram fails and shut down the pump. New diaphrams and new shear screw $99 total and good for another 5 years.

No idea yet on the oil. Will look into that. Today I swapped the fuel lines from the Racor's to try and isolate the issue. There was no change and the port engine crapped out again. Consequently, I think that the problem might just be on the port engine itself and not the fuel delivery.

I have received some good intel from SIM Yamaha regarding other things to check. I guess that's where I am headed at this point.

Interestingly, if I run the port engine at 12-14 hundred RPM, it does not fail. I have a fairly long run both up and down my creek to get to the bay and all of it is a no wake zone. So, for the last few days I have run the port engine at 12-1500 and the starboard at 600. It doesn't quit at that rpm.

Are these carburetor or fuel injected engines?

oldmako said:

No idea yet on the oil. Will look into that. Today I swapped the fuel lines from the Racor's to try and isolate the issue. There was no change and the port engine crapped out again. Consequently, I think that the problem might just be on the port engine itself and not the fuel delivery.

I have received some good intel from SIM Yamaha regarding other things to check. I guess that's where I am headed at this point.

Interestingly, if I run the port engine at 12-14 hundred RPM, it does not fail. I have a fairly long run both up and down my creek to get to the bay and all of it is a no wake zone. So, for the last few days I have run the port engine at 12-1500 and the starboard at 600. It doesn't quit at that rpm.

Click to expand...

Here's a link to another forum that talked about your problem... http://forums.iboats.com/forum/engi...oards/267270-yamaha-225-4-stroke-fuel-problem

From what they discuss.... The "F" shaped fuel filter apears to be part #16 on Sim Yamaha's engine diagrams of your engine under "intake 2".

Thanks for all the ideas. I am out of the country at the time but will look into it as soon as I get home.

I spoke with a Yam mechanic and he suggested swapping the inline check valves (on the engine to see if the problem follows. If so, obviously a bad check valve. The boat's on the trailer now and it should be easier to check some of the items mentioned above and in the thread mentioned above. Sounds like it shouldn't be too tough to sort out since so many people have had it.

Same tank.

Separate Racors, lines, and bulbs.

Fuel Injected.

Plugs not pulled. Engine idles smoothly and runs perfectly at all throttle settings. It only cuts out after prolonged ops at idle, like in a no wake zone.