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1986 Johnson 40hp fuel issues.

L

Loopy2

New member
I have a problem with a 1986 Johsnon 40hp, when we have it in the driveway you can run the rpms up with out any issues. When you get it on the water and the motor gets under load the motor seems to starve out for fuel, we have swapped tanks and gas lines thinking this may be a problem but no luck. Is it possible the fuel pump is going out? If so how do you check? does anybosy know what a good baseline is for setting the carbs on this thing?
 
Winding it up in nuetral in the driveway is a big mistake !! --------Nothing is learned by doing this.---------Your motor may be in bad shape internally, so do the following.---------------Do a compression test and post the results.----Check to see if there is spark on both wires that will jump a gap of 7/16" with a snap you can hear.-----------If these prove good then you start looking at carburetor / fuel issues.---The testing is a low cost way of finding out where the problem is.
 
Ran a compression test and am at the 135 mark, the spark seemed to be excellent also. With that said is there an easy way to see if fuel pump is bad. Took it back on lake and when running the motor we realized if we were to continuously squeeze the bulb the motor stays up on power and keeps running.
 
Having to operate the manual pump proves that the pump on the motor is not working properly.-----------Repair the fuel pump.------------If it is a VRO there are kits available.--------Or you can install a 1983 pump cheaper.------The spot to mount it is already on the block.
 
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So yes it is a VRO but the oiling system was disabled a long time ago, I am assuming it would be best then to go with the 83 pump, but will be totally lost as how to install. Do you know of any literature explaining how about doing this modification?
Here's my confused look, when I look up the pump in the parts page for my motor serial J40ELCDE the pump they have listed doesn't look anything like what is on my engine?

BTW, thanks for the help racerone, it's greatly appreciated!!
 
Order the 83 pump and gasket !----Find 2 screws ( 10-24 -NC )----There is a spot on the block to mount it .-----Just a bit of work to install it, no rocket science required for this job.
 
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