Fuel flow issues

[Larry Stamp]

I am new to the forum, so bear with me if I don't do something right: I have a 2008 Yamaha 80 HP jet, just broke 70 hours. A few years ago the gasket on the fuel sending unit deteriorated because I was not using ethanol free gas... yes, stupid and I immediately changed my ways. Since then, I have issues on occasion with the engine starving for fuel when starting up, worse on hot days interestingly. I have changed the water separation filter and fuel filter 4 times. Thinking something might have deteriorated in the fuel line bulb, I changed that too. The motor runs fine after a few minutes of "coaxing" when starting up. I have no issues with the kicker. Anyway, not sure if this is a vapor lock issue, something in the fuel line system or what. Any thoughts and direction would be appreciated. Thanks in advance! Larry

[99yam40]

have you tried pumping the primer bulb before starting ?

I do not see a 80 hp anywhere in the 2006 and after parts break downs

[TownsendsFJR1300]

99Yam, I think being a "jet propulsion", it's actually a higher HP, just 80HP to the jet.

For the OP, being so much water has gone thru the engine, have you drained the carb bowls (if carberated) or drain the VST (FI'ed) looking for any water, crap?

Plus one on priming the bulb when acting up..

Also, can you post the model # of the engine?


Possibly a F90TJR??? :

http://www.boats.net/parts/search/Ya...TJR/parts.html

http://www.boats.net/parts/search/Ya...010/parts.html



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[boscoe99]

He might have an F80TLR converted to a jet drive. Or he might have an F115TJR that is rated at 80 HP at the jet pump.

Folks don't like to disclose their models numbers. Must be top secret like a woman's age, a social security number or a tax ID number.

[Larry Stamp]

Should have put the model number in the post, sorry. It is the F115TJR, or 80HP at the pump. I have tried pumping the bulb and sometimes it helps a bit, sometimes not. I don't know that I ever got any water introduced into the system, but I changed the filters erring on the side that maybe I did. It is fuel injected so it is possible something is plugging that. Since the motor runs fine when the boat is up on plane angle and this happens when it is sitting fairly flat, it is as if some piece of crap is blocking fuel flow, but allows flow when the boat is at a different angle (if that makes sense).

[TownsendsFJR1300]

With all the water that was / is in the system, you could try running the engine
off a separate 6 gallon tank with fresh fuel. Drain the VST first, one screw and catch what comes out.

It's very possible your slushing water to the fuel tank pick up point, then the crappy running..

If that test run is successful, I suspect you'll be draining your main tank.


The leaky fuel gauge needs attention if not already fixed.



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[99yam40]

monitoring fuel pressures should tell you where to be looking if it is fuel starvation
and drain the VST to see what all is in there

[Larry Stamp]

Thanks everyone! At the risk of sounding stupid, what is the VST? The sending unit gasket is long fixed, but I am going to take a look at the fuel pickup line (or whatever it is called), inside the tank. Maybe a piece of rubber found its way inside it. Sure appreciate the expertise here!!

[99yam40]

fuel injected motors have Vapor Separator Tanks to make sure the pump in them does not pick up anything but liquid

[panasonic]

Here is the VST... item #11 in first diagram. Think you can get at the drain screw without taking intake manifold off. Scott will be able to tell you that for sure.

[pstephens46]

The F115 is like the F150. Intake needs to be loosened a good bit to rotate enough to remove VST. At least the f115 I have seen operated on. Now you may be able to drain it. Removal to get at the filter inside.

Not that hard. Requires a little patience. May want to take a few pics of fuel hoses and wires that may need to come off.

I believe there is a YouTube on the F115 VST.

[panasonic]

The F115 is like the F150. Intake needs to be loosened a good bit to rotate enough to remove VST. At least the f115 I have seen operated on. Now you may be able to drain it. Removal to get at the filter inside.

Not that hard. Requires a little patience. May want to take a few pics of fuel hoses and wires that may need to come off.

I believe there is a YouTube on the F115 VST.

How about just to drain it? Can you access the drain screw?

[TownsendsFJR1300]

Here is the VST... item #11 in first diagram. Think you can get at the drain screw without taking intake manifold off. Scott will be able to tell you that for sure.

In your second picture below, OP, double click on it. Part #1 is the drain screw
along with a washer.

It's a bit different than my 150 as it doesn't have a hose nipple and hose to drain from.

It should be accessible once you find the VST. Not being familiar with the your engine, I dare say most VST drains are accessible W/O pulling much IF ANYTHING off. Defeats the purpose...

I thought we were taking SIMPLY DRAINING IT???

My F150, a long phillips head screw driver and nothing else drains it..

[Larry Stamp]

Awesome. thank you gentlemen. I will follow up on your advice!

[Larry Stamp]

Thanks

Thanks for all the help. I stopped by the local shop before starting anything and found out there was also an in-line fuel filter behind the VST, ($70.00). Both hard to get to for sure. Anyway, I used various colored felt tip markers to color code everything I took apart as well as taking numerous pictures. I removed the whole intake manifold to access the VST and filter. I drained the VST (which was pretty clean), cleaned the small filter in it and replaced the in-line filter. Motor runs like a champ now. Only took me 6 hours, which isn't bad for someone with no mechanical abilities to speak of. Anyway, thanks again for the help, I appreciate it!