1992 Johnson 90.... Steam out of telltale.

[bigscrb15]

I have a Johnson 90 and while the boat was idling while I was waiting to load up on the trailer last weekend the overheat alarm went off. I didnt pay much attention to it and went back out yesterday to try and diagnose the problem. I idled out of the channel for about 5minutes. I then heard a noise and looked back to see steam was coming out of the telltale hole. I put the boat back on the trailer and brought it home and dropped the lower unit. The impellor seems to be fine and it is pumping plenty of water before it turns to steam. I assembled everything back together and hooked it up to the earmuffs. I let it idle and felt the stream of water. It would be cold, then warm, then very hot then steam. This would repeat over and over every 15-20 seconds. Could this still be a waterflow issue or does it sound more like the tstats need replaced?

 

[jtexas]

Re: 1992 Johnson 90.... Steam out of telltale.

with luck, it's the termostats and nothing else.

other reasons for a motor to overheat:
* blockage in the water jacket.
* inadequate oiling.
* lean burning.

 

[Craig-]

Re: 1992 Johnson 90.... Steam out of telltale.

T-stat(s) would be my bet.

 

[emdsapmgr]

Re: 1992 Johnson 90.... Steam out of telltale.

The telltale indicates relative condition of the water pump impeller. You can have a great impeller, but if the stats don't open the powerhead will overheat at idle because the cooling water can't circulate back into the midsection. One thermostat for each head.

 

[emdsapmgr]

Re: 1992 Johnson 90.... Steam out of telltale.

My concern would be for the steam at the telltale-that might indicate no water at the powerhead. The telltale indicates relative condition of the water pump impeller. You can have a great impeller and telltale, but if the stats don't open the powerhead will overheat at idle because the cooling water can't circulate back into the midsection. One thermostat for each head.

 

[bigscrb15]

Re: 1992 Johnson 90.... Steam out of telltale.

Thanks for the advice everyone... I will replace the thermostats. I helped a friend replaced his on the same engine and I am not looking forward to doing it. It is a pain to get the housing off with the springs in there and lack of room for a socket. Anyone have any tricks? Also, the cheapest place to order a thermostat and waterpump kit(figured ill go ahead and replace it anyway as its been a few years)?

 

[bigscrb15]

Re: 1992 Johnson 90.... Steam out of telltale.

Nevermind.... It appears my best bet is to order the parts right from iboats.com!! I never even looked at their online store. Prices are good and I can order everything from one place!!

 

[Sixmark]

Re: 1992 Johnson 90.... Steam out of telltale.

In the future, do not disregard the overheat alarm, if you get them hot enough you can find yourself replacing everything under the engine cover. Don't be surprised if you end up replacing pressure relief valves as well.

 

[bigscrb15]

Re: 1992 Johnson 90.... Steam out of telltale.

In the future, do not disregard the overheat alarm, if you get them hot enough you can find yourself replacing everything under the engine cover. Don't be surprised if you end up replacing pressure relief valves as well.

I definitely did not disregard the overheat alarm. It went off as I was loading the boat onto the trailer. As soon as it went off I shut down. Being that the overheat alarm and the no oil alarm are the same, I wasn't sure what the issue was. I had an issue way back where the oil injection system failed so I thought it may have done that again. After testing that system and seeing I was getting oil I decided to run the boat and see if it would overheat. I shutdown the engine before the alarm went off after I noticed steam. All I can say is thank God for my trolling motor!! lol.