Fuel problem?

[2000Johnson90]

I have a small but frustrating problem and before I just start replacing parts, maybe I can get some advice. I have a 2000 Johnson 90 Ocean Pro. I pump the bulb and it starts right up on muffs and idles just fine for about 3 minutes, then starts to bog down, shortly thereafter stalls. I feel the bulb and it is empty but not flat. When I run it and it starts to bog down I can keep the motor running by pumping the bulb quick or by increasing the throttle, after I pump the bulb or back down the throttle, it will run for a few minutes and eventually bog down and stall again.

I have replaced all fuel lines, checked the vent, and added new gas, and get the same problem and behavior. Does anyone have any ideas? I'm thinking it could be a weak fuel pump, running fine with the line fully charged, but doesn't have enough to keep pumping enough fuel.

Again, it starts right up and runs fine for about 3 minutes, and the bulb is empty when it stalls, when I pump the bulb and turn the key, it starts right up and does the same thing again.

Any help is great, thanks.

 

[EARLS BOAT]

Re: Fuel problem?

sounds like a fuel pump problem to me.

 

[kenmyfam]

Re: Fuel problem?

If it is venting O.K. then I would suspect the fuel pump being on it's way out.

 

[Chris1956]

Re: Fuel problem?

That motor likely has two fuel pumps on it. The first is the OMS pump, which may not be rebuildable. The second is the vapor pump, which is likely your problem, and should be rebuildable for small $.

 

[tashasdaddy]

Re: Fuel problem?

0433352 PUMP ASSY., Vapor 1 $83.18 USD

 

[Mas]

Re: Fuel problem?

Check this out:

http://continuouswave.com/whaler/reference/primer.html

MAS

 

[2000Johnson90]

Re: Fuel problem?

Thanks for all the replies, all very helpful information. I like the tip about mounting the bulb vertical, I understand it will help the bulb charge the line, but does it also reduce line friction for the fuel pump, thus making it easier for the pump to do its job?

About the OMS, there is none on my motor, not unless I am just missing it. I pre-mix the fuel because if I don't, well, there is no where else to put the oil, no oil tank for the OMS. I read that these motors come with OMS, but that most people remove/bypass it and pre-mix, perhaps that is what the previous owner has done.

One final thing, I've yet to run it in the water this season, so I wonder if testing it on the muffs could be the cause of lower engine vacuum, or less pump efficiency?

Thanks again.

 

[Chris1956]

Re: Fuel problem?

If the fuel primer bulb goes flat or empty, examine the fuel line from the tank to the bulb, for restriction. Also examine the antisiphon valve in the fuel tank pickup fitting.