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1990 Johnson 60 hp overheat alarm

J

Jfdjeep

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I have owned this boat for 2 years without problems. I'm in Illinois so I believe it has spent it's life in fresh water. Motor is 1990 VRO 60 hp Johnson remote with power tilt/ trim. It's on a 24' pontoon. After about 2 minutes at full throttle the overheat alarm sounds. That's about 3,200 rpm on my boat. I pull back to idle & alarm stops in about 30 seconds. I have good water from telltale. I can run 2,500 to 2,800 rpm all day but get the alarm if I go near or over 3000.

I'm a competent auto mechanic but new to outboards. Want to know where to start. Any help is appreciated.

Thanks
John
 
That usually indicates a failing impeller. At any rate, the first step is to drop the lower unit to inspect the pump assembly.
 
Thanks Joereeves. I'm going to try the pump kit first. We're going to the lakehouse tomorrow so I'll let you know what happens
 
Flyingscott The rpm seemed low to me too but I am relying on the one in the dash. Motor sounds like its running faster. I'll have to bring another tach out there to check it. I haven't had a chance to install the impeller/pump kit yet either. I'll post results when I do.
John
 
Racerone I'm not sure where telltale comes from. The pump kit I received tells me to make certain changes to the thermostat & telltale too. I'll let you know when I get back out there
 
60 HP sound under power for a 24' pontoon, what size prop do you have there, overloading an engine kills it, beside water pump issues that could be a reason for overheating.
 
I have not yet replaced the pump. Took the boat out this weekend & got the the alarm again. This time she went into slow mode. Even after sitting off for an hour, upon starting still would not run above idle. I've been reading other threads here about similar problems. My questions are;

Shouldn't the slow mode deactivated aftrr motor cools down?

Does this mean I have a bad power pack?

I plan to replace pump anyway, is it a good Idea to pull the head & flush the system? I've read about problems with scale build up in these old morors.

Should I also change the thermostat?

Any input is appreciated.
Thanks
John
 
Man my is doing the ooposite going off at low rpms and then clearing up and going away once i get going. I feel pretty sure mine is a false alarm.
 
Jfdjeep said:
I have not yet replaced the pump. Took the boat out this weekend & got the the alarm again. This time she went into slow mode. Even after sitting off for an hour, upon starting still would not run above idle. I've been reading other threads here about similar problems. My questions are;

Shouldn't the slow mode deactivated aftrr motor cools down?

Does this mean I have a bad power pack?

I plan to replace pump anyway, is it a good Idea to pull the head & flush the system? I've read about problems with scale build up in these old morors.

Should I also change the thermostat?

Any input is appreciated.
Thanks
John
Click to expand...

I would change thermostat for sure. I am about to change mine on my 79 140hp Johnson. I already changed the water pump and the lower units oil seals. I heard someone say that the tilt and trim sending unit can cause this alarm.. does yours have a trim gauge on your dash? I am curious if this is really true or not.
 
Racerone I honestly forgot to look where it came from. We were on a quick stop at lake & did not have time to pull the cover. This weekend I'm going there just to try & figure this thing out.
 
Racerone the telltale comes from the port side. I believe that is the exhaust manifold cover. I think the slow mode was a low fuel issue. I'm back to just overheating at full throttle. I have a pressure guage on the dash tied into the telltale. Its around 6 psi at idle then goes up to 16 psi at speed. This leads me to believe the pump is fine. I still plan to replace it next month when i pull the boat out but I dont think it is causing my overheat problem.
I can run all day at 2400 rpm. Over 3000 rpm & it quickly overheats.
I am at the lake for the weekend. I appreciate any input.
Thanks
John
 
Racerone the telltale comes from the port side. I believe that is the exhaust manifold cover. I think the slow mode was a low fuel issue. I'm back to just overheating at full throttle. I have a pressure guage on the dash tied into the telltale. Its around 6 psi at idle then goes up to 16 psi at speed. This leads me to believe the pump is fine. I still plan to replace it next month when i pull the boat out but I dont think it is causing my overheat problem.
I can run all day at 2400 rpm. Over 3000 rpm & it quickly overheats.
I am at the lake for the weekend. I appreciate any input.
Thanks
John
 
There was a service bulletin that came out in 1994 , yes 1994 to relocate the telltale to the top of the block.-------------most important on some installations such as a pontoon boat.--------Amazing that this has not been done on yours.
 
Thanks for the info Racer. I'm looking at the instructions for the new pump. It says "If using a water pressure guage, the engine pickup must be relocated to the exhaust cover"
My system comes out of the exhaust cover to a tee. One hose goes to the guage & the other to the telltale.
Should I leave the guage hose attached to the exhaust cover & move the telltale?

Also
This pump kit also have me a new thermostat cover & spring with instructions when to use which.
I appreciate your help
John
 
I've heard of the telltale relocation. I am running a 75 HP j75trlcim with the tell tale at the sock location on the port side. Should it be relocated?
 
ericulvila said:
I've heard of the telltale relocation. I am running a 75 HP j75trlcim with the tell tale at the sock location on the port side. Should it be relocated?
Click to expand...

You should have started your own thread for this but no you do not need to move your tell-tale. Your motor is not part of the service bulletin
 
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