200 hpdi bogging down again

[Felton]

A little back round on my motor last fall my motor started to bog down. I changed the vst filter the can filter and the filter inside the plastic bowl then replaced one of my mech. fuel pumps. The fuel pump fixed my problem.

On my way home Wednesday my motor started to hesitate. It was just a little at first then more and more buy the time I got to the marina I could only idle. So I figured my other mech. fuel pump went out. I replaced it Thursday. Friday I ran 25 miles offshore and no problems until on the way home started to hesitate so I went and pumped the bulb two or three times and off I went no problem. I ended up having to pump the bulb 3-4 more times be for I got home. Today I can't get it much above 1500 RPMs.

I checked some of the fuel connections, they seem fine. The only thing I noticed that might not be correct is the plastic bowl will start off full then run down to about where the filter is. It seems that I bog down more when the fuel level is lower in that bowl. I am debating about replacing that bowl. Any other suggestions. Is there a way to narrow down where my problem is coming from.

Thanks for all the help

Felton

[Hamfisted]

Bowl gasket...

Take a look at the O-ring gasket on the fuel bowl. I've seen ethanol causing swelling and poor sealing, allowing air to get sucked into the bowl by the mechanical fuel pumps, instead of pure fuel being pulled in. Then you get a bunch of air in the VST and high pressure pump/lines and the motor runs like chit. That's why when you pump the primer bulb it fixes it for a short period. I think Yamaha is gonna have to come up with an ethanol compatible O-ring or something. Also make sure the cellulose filter inside the bowl is yellow in color and not brown or worse. Ethanol doesn't agree with that filter either.



- Mike

[Felton]

What about air in the plastic bowl? Is there suppose to be air in there? The air comes down to the bottom of the filter.

Or how about the gasket behind the fuel pump it was torn on the side. Would that effect anything?

I will take a look at that gasket in the vst.

[jb123]

a torn gasket would definatly affect the performance but most likely /HoPEfully tore from removal.

[Felton]

I don't know if I tore it or not. What does that gasket do? I though it just gave it a cushion so it was not metal to metal. The part I am talking about is 650-24431-A0-00. Its only a $1 part so I guess I might as well replace it any ways.

[Felton]

Ok so the O-ring on the bowl looks great. I checked the fuel pump that I put on Thursday and it is shot. What could make a fuel pump become shot so quickly?

I hope the dealer ship will replace.

[Tucker]

What do you mean by shot? Is the diaphram ripped? A few pics would be great. Got some pretty sharp cookies on here that will figure this out if they can see it.

I had a bogging down about a year ago on my 94 200 Pro V, what was fixed was the stator, by a repair shop, tech said that upon accelatrion the voltage output did not go up therefore the plugs were not firing as hot as they should and not burning all the fuel. When I pushed my hotfoot all the way down the engine bogged, took a while to get on plane and would then only go about 40mph wide open. I also thought I had a carb problem, might try having the stator checked.

[Felton]

Tucker "What do you mean by shot?"

So I have been told when you loosen the bolts to the Mech. fuel pump if it leaks it is not working correctly and needs to be replaced. Mine poured out when I loosened the bolts. So Yes I am assumeing the diaphram is ripped.

I went down to the dealership and they said the part is under warrenty so they ordered another one. I will replace it and see what happens.

[Felton]

I replaced the bad fuel pump. Now it will rev up a little more but when I throttle back and try and give it gas again it stalls and dies. Any one got any ideas?

The plastic bowl doesn't get air in it anymore. I also replaced the gasket from the pump to the motor.

[Tucker]

Not sure what you mean by gasket from pump to motor. My money is still on air in system. Some heavyweights need to chim in here. If it were me I think I would pull and block off the fuel line from the vst, pull the line off the main fuel tank and hook up a might vac and pull a couple pounds of vaccum. If the guage drops there's an air leak somewhere. Poster above mentioned the stator. That thing is voodoo to me; I haven't the fogiest idea how to check that. Have you check the manual on that one?

[Felton]

I believe there is compression coming out of the motor to those pumps. That is what makes the mech. pumps work. Its the gasket inbetween the fuel pump and whatever it is mounted to. Part #650-24431-A0-00 Thats been replaced now so no need to worry about it.

I will check for an air leak and look into the stator what ever that might be.
Thanks for all the help keep the info coming.

The engine does not die any more it just boggs down.

[Felton]

It is back to if I pump the primer bulb I can rev it up. So hopefully it is like you said about air getting in somewhere. The thing that gets me is I can only get it to rev up by doing it slow if I try to fast it just boggs down.

[Tucker]

Dude this sure sounds like the high pressure pump screen is clogged, but you said you cleaned it. Do a search, I've read back to about page 110 and I recall a post about a guy that had is engine worked on by a pro. He changed a lot of stuff and the problem was finally the pressure regulator valve on top of the vst. There's a procedure in the shop manual about how to test it. If the plastic filter next to the engine isn't getting air in it, you said it wasn't, maybe the pump isn't filling the fuel rail fast enough. Just a shot in the dark. Need boats.net, jb, bigfish, or any of those guys to chime in. Going to keep an eye on this one.

[Felton]

well I guess I will try cleaning the vst filter again.