1995 130 Johnson Overheat - Port Side

[Striper500]

My 130 Johnson seems to be a very sensitive motor. Last year I ran it all summer without thermostats. I inserted the stats again in December and ran it for a whole day - no problems. I used the boat this year and noticed that the port side was on the hot side - noticably different from the starboard side. The water pump and stats were replaced last year. I would really like to run the motor with stats. Any suggestions ? If the head was cloggede, wouldn't running it for 100-150 hours last year w/o stats potentially resolve any problems ? any insight would be appreciated.

Thanks.

Chris

 

[Dhadley]

Re: 1995 130 Johnson Overheat - Port Side

One head may have a slight blockage or scale build-up. You could try swapping the heads and see if the problem follows the head but while they're off why not clean them? And then make sure you swap them just to see.

You are using the black vernatherm assemblies, right? What spark plugs?

 

[Striper500]

Re: 1995 130 Johnson Overheat - Port Side

I am currently using QL78YC Champion Plugs. The thermostat assemblies are black plastic with rubber boots.

I read on this forum that you can take the thermostat covers off and hook up ear muffs (engine off) to potentially flush the heads. Does this work ? Can I cause harm to the motor ?

Thanks Chris

 

[HighTrim]

Re: 1995 130 Johnson Overheat - Port Side

How hot are we talking? Can you still hold your hand on it for a 1, 2, 3 count? Will sprinkling water on it cause the water to sizzle? Best yet, do you have access to an infrared thermometer?

Flushing the motor will cause absolutely no harm to the motor. I usually like to do this when I change the water pump and thermostats. Use compressed air or the garden hose to flush from the water line up to the t stat housing, then backflush down from the t stat housing to the water line. Re install t stat then repeat with second t stat, flushing the water from the water line up, then backflushing down.

If it is overheating, you may want to test your alarm as it should sound when this happens.

It was also a good idea re installing the t stats, running without is trouble.

 

[Striper500]

Re: 1995 130 Johnson Overheat - Port Side

It can get pretty hot. While the alarm didn't sound, it did earlier last year. Hence the reason why I ran it without stats all last year. Just curious, I have run two different motors for 3 entire seasons w/o stats and had no real problems (except in the winter when the motor was running abnormally cold)

What are the risks to running it without stats ?
I assume if I am using compressed air I need to drop the lower unit ?

Thanks Chris