Johnson 90 won't turn up

[Salty Tricks]

My 1985 starts up fine and actually runs well for a few minutes then slows down. When I press the choke it surges with full power. I guess this means I have a fuel problem? I recently changed the water separator. Is it the quick disconnect? Is the inline plastic filter under the cowling just a filter? Can this be replaced with an aftermarket inline fuel filter? Any other suggestions? Thanks

 

[JB]

Re: Johnson 90 won't turn up

Sounds like a fuel supply problem to me, Tricks.<br /><br />Check your fuel tank vent, fuel pickup and lines for restriction. Another possibility is a weak fuel pump.<br /><br />Good luck.

 

[Salty Tricks]

Re: Johnson 90 won't turn up

I checked the vented fuel cap on the tank (Boston Whaler Montauk)but still slows down after running good for several minutes. I purchased a new fuel disconnect and an inline fuel filter (under cowling). I will install these tonight. Before launching I installed a new fuel/water separator. Are the older VRO pumps rebuildable with a kit?

 

[o/b tech]

Re: Johnson 90 won't turn up

You might want to consider upgrading the vro pump to a four wire kit that has an audible no-oil warning system built in. these new style pumps are more reliable than the first generation vro. It may be more expensive but offers better protection in the long run.

 

[Salty Tricks]

Re: Johnson 90 won't turn up

O/B Tech<br /><br />Somone told me that if I squeeze the primer bulb while running and got no change in RPM it was unlikely the VRO. I tried this and there was no change. He suggested water in carbs. Can the fuel in the carbs be drained off?

 

[moderator1]

Re: Johnson 90 won't turn up

unscrew the bowl-nuts/jet covers on each side of both carbs-4 screws total. That will drain the bowls.

 

[Dhadley]

Re: Johnson 90 won't turn up

I'd bet on dirty carbs. Been sitting awhile? (Typical scenario -- "It was fine last fall when we put it away for the winter")<br /><br />Also when you activate what you call the choke (its actually a primer -- it injects fuel into the motor) that proves the pump is working. If the pump was not delivering fuel to the carbs, it wouldnt deliver fuel to the primer either.

 

[Salty Tricks]

Re: Johnson 90 won't turn up

Thanks all...will check this out tomorrow