(Case closed) VST Filter? 06' Yama F150

[nocturn]

So now ive had the 215CC up and running for the past month and have logged about 14 hours on her. Some may remember I had her on the trailer for the last 4 years due to back surgery. Before putting her back into use, I changed the engine fuel filter, the 10 micron in-line F/W separator, Engine Oil and Gear Oil. Ive been loaded her with fresh fuel, Sea Foam and Ring Free for 3 tank loads over the month. The Yamaha F150 has been purring like a kitten up until a few days ago.

I started to notice a sputter when I ran the throttle up. It wouldn't do it all the time but when it did, it sounded horrible. Almost like the engine was under revving for a split second. Fast forward to last night and noticed my RPM's at WOT are way down from the previous trips. My WOT is generally 37-39 mph @5600 rpm. Last night I could barely make 29-30 mph @ 5100 rpms.

I'm going to look into a few things first. I'm going to replace the plugs, look at the throttle cable linkage and adjust if necessary, replace engine oil and I'm going to replace the VST filter. Something is making me think that between 250 hours on the clock, being in storage so long, and me dumping all the additives into the fuel system, the VST filter is probably clogged or close to it. Sound reasonable to assume?

 

[Push&Pull]

If you still had ANY fuel left in the tank while it was in storage for that length of time......and you didn't drain the tank.......alas, you need to do that now. Additives don't work for everything. You need to drain the tank and all the lines leading to and in the motor. Plus bowls, filters, fuel pumps, hoses etc. Clean it all out.

Then, you can do this or not at your own peril.......but only use ethanol "free" fuel (Rec90).

 

[Push&Pull]

I look at fuel kinda like the water situation when you're out on the big pond (ocean).
"All that water and not a drop to drink".

Contaminated fuel is like all that saltwater when it's an emergency and you are stranded way offshore...........
The fuel will typically let your engine run for awhile to get you offshore and then when it hits the contaminated fuel.......it quits and then you have
"all that fuel and not a drop will work".

Moral of the story.......I carry emergency water on board and treat my fuel like it's my emergency water.

 

[nocturn]

Yeah, I know the routine.

Although I had about 10 gallons of 3 year old Sea Foamed fuel in the tank, I did flush almost everything before I put new gas in. Old gas worked like a charm in my lawn tractor. Only thing I didn't do was replace the VST filter because its such a hassle to get to. So im thinking the ring free probably loosened up a bunch of sediment/goo in the line and is restricting fuel flow through the VST.

I'll probably pull and clean the injectors while im in there as well.

 

[peaceinthewood]

Yeah, I know the routine.

Although I had about 10 gallons of 3 year old Sea Foamed fuel in the tank, I did flush almost everything before I put new gas in. Old gas worked like a charm in my lawn tractor. Only thing I didn't do was replace the VST filter because its such a hassle to get to. So im thinking the ring free probably loosened up a bunch of sediment/goo in the line and is restricting fuel flow through the VST.

I'll probably pull and clean the injectors while im in there as well.

i have the same engine as you and i started to notice slower speeds less rpm's and uneven idling the previous owner also had long periods of time without using it ... had the vst filter changed and fuel injectors cleaned .....end of problem

 

[nocturn]

i have the same engine as you and i started to notice slower speeds less rpm's and uneven idling the previous owner also had long periods of time without using it ... had the vst filter changed and fuel injectors cleaned .....end of problem

Nice, man. Were you having RPM drops as you went up in throttle and lower RPM's at WOT also?

If you don't mind me asking, what did the service run you?

 

[peaceinthewood]

150 for the injectors (so worth it) and he did a few things and charged me 2 and change i dont remember all but one thing was he changed out my thermostat as well . no 5500 rpm like 40 mph top end my top end used to be 30 to 32 mph and the rpm 4800 something like that and
rough iddle uop and down

 

[peaceinthewood]

Nice, man. Were you having RPM drops as you went up in throttle and lower RPM's at WOT also?

If you don't mind me asking, what did the service run you?

ohh and of course non ethenol fuel ONLY!

 

[nocturn]

150 for the injectors (so worth it) and he did a few things and charged me 2 and change i dont remember all but one thing was he changed out my thermostat as well . no 5500 rpm like 40 mph top end my top end used to be 30 to 32 mph and the rpm 4800 something like that and
rough iddle uop and down

Wow, yeah! Sounds like you made huge gains! Nice.

My T-stat should be fine (knocks on head). I've only got 230 hours on the clock and a T-stat failure at this point in its life would be really uncharacteristic.

I use non ethanol gas almost all the time. I have a marina about 10 minutes down river that carries non ethanol. Every once in a while when I head out the eastern shore of Va, I'll get Exxon Premium and add a fuel stab. I'll burn all that off in 1 day.

 

[nocturn]

Well, I changed out the pre-VST filter, the VST filter, fuel filter and cleaned the fuel injectors. Still a loss of rpms so I'm thinking have a bad injector. Tonight I'm going to run a few tests and find out which one is toast.

Any good places online to purchase oem Yamaha injectors without cleaning out my bank account? Thanks.

 

[nocturn]

It was the fuel injectors. I replaced all 4 with refurbished ones for $80.
Just before I swapped out the old injectors, I ran a Seafoam shock mixture through the fuel line. 3/4 gal gas to one 16oz can of Seafoam, run @2500 rpms for 10 min, shut off engine for 15 min and run mix until empty @ 2000rpms. Carbon blow out for about 30 seconds.

Replaced old injectors and took her out on the water. 5900 rpms @ 44mph wot. Freaking beautiful.

Case closed.

 

[NCangler]

Thanks for sharing the solution to the issue.