2001 Johnson 80 Motor Trouble

[Kylerobbins]

2001 johnson 80 hp jet, 2002 lowe roughneck 1655 tn

A week ago I was running my boat up a river here in alaska. Boat was running great, didn't skip a beat, runs about 6500 rpms. Decided to run up a skinny slough id never been up, well it turned out to be to skinny. Had to stop, had to trim up cause the water was so shallow, i idle out of the slough while trimmed up enough to not suck up any rocks. The motor idled great the whole way out of this slough. When i got back in the main stem of the river i gave it full throttle and it idled to about 2200 rpms and didn't have enough power to move me up or down river. i stopped and cleaned the jet unit out and cleared all rocks and tried again, still didn't have enough power to move me. when i trim up to where the only the foot/shoe is in the water the boat will take off like it normally does until the whole jet unit is under water then it will drop down to 2200 rpms and not move. i idled it back to the boat launch and brought it home, checked everything in the lower unit and everything looks great besides the impeller being a little dull. Checked the motor and all 4 cylinders have perfect compression. Only problem i noticed is the water pumped was seized up but the it pissed water good the whole time i idled it back to the boat launch, idles perfect in neutral. Im stumped and so is every outboard mechanic that I've taken it to. Any and all help would be appreciated.

 

[boobie]

Do a compression test on it and then a cylinder drop test.

 

[Kylerobbins]

I already did. It runs perfect when there isn't a load on the motor, full rpms on all 4 cylinders.

 

[racerone]

???------Getting lots of RPM in nuetral means nothing.

 

[Kylerobbins]

Racerone the motor runs good with full rpms when there's no load on it, when I trim down to where the motor is fully under water and has a load it bogs down

 

[flyingscott]

Racerone the motor runs good with full rpms when there's no load on it, when I trim down to where the motor is fully under water and has a load it bogs down

Revving it up in neutral is a useless test you could take 2 spark plugs wires off that motor and rev it in neutral means nothing. The motor needs all 4 pistons working together to run in the water if less than 4 are working then then you will have the problems you are having. Do what racerone said also how was the waterpump siezed. Then when that is done check the flywheel key and the fuel pump.

 

[bob johnson]

well it seems like you overheated the motor....don't have any idea how you could supply enough water to your motor with no water pump!!!... S.L.O.W. comes to mind, but I am guessing you turned the motor off and it cooled and you still have the issue...correct? because to disengage SLOW you not only have to cool the motor, but you have to turn off the key.... then the system is reset.....what is that jet HP based on???? a 115 hp motor???.......its not a Ficth is it???

bob

 

[Kylerobbins]

Bob 115 to the power head 80 to the jet. I don't under stand how after the motor sitting for 2 weeks and when I turn the key on its still giving me a constinous beep on the VRO beeper. I know it's not over heating cause there's no way it's hot after 2 weeks. The motors getting oil cause I ran it back to the boat launch which took me an hour, the motor would've blew up without oil after 15 min

 

[boobie]

Check for a tan wire being grounded somewhere.