Johnson VJ90TLESB, tell tale cooling stream too hot to put hand under

[astampfel]

I was running my engine, 1990 90 Hp Johnson, on ear muffs. For the heck of it, I decided to put my hand in the stream. Wow, it was super hot!!! Is it supposed to be this hot? The stream is very strong, but it is also very hot! In contrast, the stream on my 2005 Yamaha 2 stroke is cool to the touch.
I'm going to change my thermostats, but I don't know if the hot temperature of the tell tale effluent is a problem.

 

[Bosunsmate]

Re: Johnson VJ90TLESB, tell tale cooling stream too hot to put hand under

how do the heads feel?

 

[keefallan]

Re: Johnson VJ90TLESB, tell tale cooling stream too hot to put hand under

That doesn't seem right. My 112 doesn't have water that hot. As stated, check the head temps to verify. Also how long does it take for the water to get that hot?

 

[emdsapmgr]

Re: Johnson VJ90TLESB, tell tale cooling stream too hot to put hand under

A strong telltale indicates that the impeller is doing it's job. Not that the water is circulating through the block. If either stat is stuck closed, that head will overheat and it could cause the telltale to heat up also. Good call to change both stats. Also, check: inside the thermostat housing is a plastic plate called a valve body. There is an oval hole in the center (top) that lets water get around to the backside of both stats, causing them to open. If that small oval hole is plugged with debris, the engine will overheat, even with new stats. (the older V4's have two small pinholes instead.)

 

[Bosunsmate]

Re: Johnson VJ90TLESB, tell tale cooling stream too hot to put hand under

You could also check the hoses to the thermostat to see if they a hot like that telltale, they shouldnt be if its flowing correctly.

On a similar motor to this I increased that hole a little with a drill to minimise the chance of little debris filling it up.
I figure it wont affect it much, maybe take a bit longer to heat up.
I can see why they later changed that system.

 

[metriccrescentwrench]

Re: Johnson VJ90TLESB, tell tale cooling stream too hot to put hand under

Before doing anything I'd suggest finding out what the temperature of the heads are at idle. They're supposed to be around 140 ish (deg F), which feels plenty hot.