Logo
FULL SITE MENU

Yamaha fuel/filter/vst ?

D

dward

Contributing Member
I have a pair of Yamaha 4 stroke 115s (about 03 vintage) and we went through the vst, injector cleaning last year due to running bad gas out of an auxiliary tank through the motors. We've probably run a couple hundred gallons of gas with ethanol (with startron) through the motors since.

On my last trip to Florida (I'm in MN) one of the motors would accelerate up to full RPMs (about 5000) and then over 30 seconds, slowly back down to about 3800 and stay there. When I back off on the throttle and then floor it again it would go back to full rpms and back down each time. The tech came out and checked fuel pressure which was fine and as it idled fine he said it was the vst filter acting up. I don't think he plans to clean the injectors, just replace the VST filter, and all filters up stream.

This was last Saturday and I had to head home on Sunday so repairs will be completed this week. Looking for opinions on his plan of action??

Also, I looked at the fuel water separator and it's a quicksilver which I think is a 25 micron filter. I asked to have a 10 micron Yamaha filter installed. I've heard there is a Racor 2 micron filter available. I would rather filter the junk ahead of the motors.......any opinions on going to the finer filter or maybe putting them in series???

Thanks - Dan
 
Last edited:
justintime said:
finer filter is great, but you can clogg them up twice as quick

startron is snake oil
Click to expand...

As I'd like to shoot the engineer that put the VST behind the intake, I'd rather change an accessible filter myself than pay $500 to have a mechanic tear the intake off. I've had tanks cleaned and filters replaced (including addition of 10 micron Yamaha filter) so hopefully we can stay ahead of the curve now.

JIT.........I appreciate your feedback, is there a stabilizer that you believe in??

Thanks - Dan
 
Yes I agree, Marine Stabil.I have a 225 VMax and didn't get to use it for 11 weeks.I over treated a little bit with Marine Stabil.Took it to the water and it ran like a champ!No trouble at all.
 
Thanks for the feedback.

The mechanics #2 man came out and took the intake off and removed the VST tank. I was on the dock and when he handed the VST tank to me it had the filter in the bottom. When I saw that it seemed odd as I figured it should be attached to the pump which he hadn't removed. How positively do the filters snap on to the pump? He put things back together with new filters from VST up stream on motor and 10 micron yamaha filter at separator. Didn't do anything to injectors.

When we took the boat out it was actually a bit worst than before and then #1 mechanic came out. I wasn't there but my brother said he ran Sea Foam through the system for a while and then the boat ran great. #1 said the "fuel pressure regulator" was stuck/sticking and needed to be freed up. He said it should be replaced eventually.

I'm wondering if its possible that the VST filter wasn't installed properly and it came loose?

I hadn't heard of the pressure regulator before and want to understand what really happened to clear things up?

The mechanic put sea foam in the water separator filter and ran through the engine, I"m wondering if this is a simple way to "treat the engines" if I'm going to leave them set for a while?

Appreciate any feedback Thanks - Dan
 
Back
Top