83 Johnson 7.5 weirdo

[Lee5267]

I have a couple questions for you smart guys. My motor starts and runs good but once you run at WOT for a while and it warms up. If you stop and then try to start right after that again it is pretty sluggish and has less power. Question two is that when at WOT there isnt as much of a stream coming out of the pee hole and the water coming out gets considerable hotter than when you are just putting around. Is this a normal occurance? Doesnt really seem like it actually overheats but I cant account for the sluggishness. Carbureator or plugs?<br />Thanks

 

[jim dozier]

Re: 83 Johnson 7.5 weirdo

I would in fact check for overheating. You may be marginally OK with the water pump at WOT but the engine temp may be at the high end of normal and when you slow down the leftover heat overcomes the water pumps ability to cool the engine at slow speed. My guess is if you let it sit long enough to cool down the sluggishness goes away. You should be able to touch the engine block for about 5 seconds between the flywheel and the cylinder head. Do this after a WOT run and report the results.

 

[blueboat1]

Re: 83 Johnson 7.5 weirdo

Are you running a thermostat? Sounds like a possible symptom. Good luck.

 

[Lee5267]

Re: 83 Johnson 7.5 weirdo

no, I took the thermostat out earlier to make sure it wouldnt a problem. Could it be because I am not running the thermostat? Also the motor where the spark plugs are like at the piston heads gets pretty warm but the other part doesnt like right under the flywheel.

 

[jim dozier]

Re: 83 Johnson 7.5 weirdo

Doesn't sound like its overheating then, the heads run hotter than the block normally. You might try pulling the airbox off if it has one and looking in the carb throats when it acts up. Check to see if its leaking gas, maybe a stuck float. When it acts "sluggish" how long do you have to run it before it runs normal again.

 

[Lee5267]

Re: 83 Johnson 7.5 weirdo

I looked to see if maybe the timing was off at the cam and there is one big arrow and two small marks and I changed it to be on the big arrow. Did seem like maybe I wasnt getting full throttle when I looked at the linkage and everything. Put the thermostat back in as well and am going to go try it out and see if anything is better. Spark plugs looked good too. If you come up with more Ideas let me know.