yamaha 225 4 stroke, 2004 model year

[general5093]

I have a 2004 Yamaha 225 4 stroke. my motor has recently developed a problem - it used to max out at 5800 RPM. Now, the engine only gets to 4200 RPM and my speed is compromised. Idle is good and engine seems to run fine, but it simply won't get to full speed. I have changed plugs, the fuel filter, and the water separator filter. No luck - same problem. I did find a bad coil, changed that too, but again, no luck.
Any input on what may cause such an issue?

[rodbolt17]

I doubt you found a bad coil.
however your symptoms are typical of a clogged VST filter.
all the fuel that motor burns goes through a filter about the size of a pencil.

[general5093]

Slow speed

I did previously change the VST filter - could it have clogged again? Maybe another issue as well?

[99yam40]

I am sure if you monitor the rail pressure it will tell you if there is a restriction

[boscoe99]

Certainly fuel rail pressure should be monitored.

Did you change the filter between the lift pump and the high pressure pump?

[BlueberryHill]

I had a similar problem on my 2006 F225. Have you changed your "F" filter. If there is restriction it will prevent fuel flow to the low pressure lift pump. If the "F" filter is new...you may have an injector concern.. How many hours on the motor?

[boscoe99]

What some refer to as an "F" filter will restrict the flow of gasoline to the high pressure pump.

The filter in question is covered by a plastic shroud so at times it gets over looked.

[general5093]

2004 Yamaha 225 slow speed

***, this F Filter is where I'm going next. The posts are very helpful. I have spent over $3,000 on mechanics with no luck yet....thanks for the tips and I'll report back in....that diagram is a huge help too....many thanks, more to follow

[99yam40]

you do realize you can find out if there are restrictions without replacing parts by testing.
I would think the mechanics would have done testing to start out with

[general5093]

2004 225 yamaha

to the earlier question, my engine has 2,700 hours on the motor....getting up there

[pstephens46]

to the earlier question, my engine has 2,700 hours on the motor....getting up there

Congrats! Always encouraging to see high hour motors. Fairdeal is good for at least another 1000....

[rodbolt17]

2700 hours? she aint broke in good yet.
do the maint or pay the repairs.
always the customer choice.

[oldmako69]

I've got your engine(s). 05 F225TURDs. No pun intended, but a reasonable assumption.

I did all the things you've done and pulling and cleaning the injectors was the solution. There's a guy in ND who does them for 17 bucks a piece. His turn around time is very quick. I mailed mine out and had them back in a week. The engines then spun up to 5800. That was early this spring and perhaps 75 hours ago. Today, they won't spin past 5100 again and No 1 runs like hell in gear at low rpm (1100-1500).

I keep reading how great these engines are. Still waiting.

I'm anal with fresh fuel and filters. Stabil and Startron with every fillup. I've gone over every inch on the fuel delivery side. Pulled the VST's, F Filter and found zero dirt, etc etc. New pumps.

They run great for a while, then slide back.

[pstephens46]

I've got your engine(s). 05 F225TURDs. No pun intended, but a reasonable assumption.

I did all the things you've done and pulling and cleaning the injectors was the solution. There's a guy in ND who does them for 17 bucks a piece. His turn around time is very quick. I mailed mine out and had them back in a week. The engines then spun up to 5800. That was early this spring and perhaps 75 hours ago. Today, they won't spin past 5100 again and No 1 runs like hell in gear at low rpm (1100-1500).

I keep reading how great these engines are. Still waiting.

I'm anal with fresh fuel and filters. Stabil and Startron with every fillup. I've gone over every inch on the fuel delivery side. Pulled the VST's, F Filter and found zero dirt, etc etc. New pumps.

They run great for a while, then slide back.

And somehow you are still getting shtty fuel....how do we fix this?

Fairdeal runs E-10 with success...I don't know

[oldmako69]

I don't know that I am getting shitty fuel. Yes its shit E10, but at least its fresh. I just know the results. IF my filters were routinely clogged, then I might agree with you. My VST's were spotless. To be fair, there was a tiny bit of pepper flakes in the VST screen, which could be indicative of the fuel lines downstream from the Racor corroding from within.

I typically buy top tier fuel from busy filling stations and cart it to the boat. The only occasional marina gas I buy is from a busy place recommended by the local Yam mechanic, and their fuel is pre-treated.

I put about 135 hours on the boat since last Sept. Not a ton of use, but more than many.