150 Johnson thermostat

[Zaxxon II]

I just installed a new tach and ran the motor (2000) on the muffs. Tach worked fine, but I noticed that the pee stream was cold even after running several minutes. The cylinder heads were hot to the touch (I couldn't hold it longer than about 5 sec). Water pressure gauge was registering when reved(but I don't know how much). My real problem is I don't have a manual and don't know where the thurmostats are even located. Any help will be appreciated.

 

[Dhadley]

Re: 150 Johnson thermostat

It depends on which 150 you have. Post the model number so we can "see" it too.

 

[Zaxxon II]

Re: 150 Johnson thermostat

Sorry for the lack of info. I thought I had it. The engine is a 2000 J150PL. There are 2 round protruding caps with about a 3/4 nut as a part of the cap on each cylinder heads that I thought might be the thermostat but I wasn't sure. While I'm at it, there is a brass 7/16 bolt on the right side middle cylinder head (between two head bolts) and on the other side there is a threaded hole for a similar bolt but no bolt. Do I need one and what is it for.

 

[Dhadley]

Re: 150 Johnson thermostat

OK, its a 60 degree 150. Great motor. Yes, the thermostat assemblies are behind those caps. The holes the brass plugs are in is for the fitting for the water pressure gauge. Thats where it reads pressure. Where is yours reading from? The threaded hole is for a temp sender.<br /><br />You need to find out how hot it is getting at idle. It should be fairly warm. You may not have a problem at all. Does the hot horn sound?

 

[Zaxxon II]

Re: 150 Johnson thermostat

The horn does not sound. I was only concerned because the pee water was so cold the the heads were hot to the touch. The water pressure sensors are in the middle of the head. The brass bolt I was talking about is on the outside of the mittle cylinder head right between two of the side head bolts (on the right only). 6the bolt has locktite on it the other side has an empty threaded hole with a bevel at the inside end. Thanks for the help on the thermostats.

 

[Zaxxon II]

Re: 150 Johnson thermostat

Bump : about the brass plug on one side only, and to ask if I can tell if anything is wrong with the thermostats when I pull them and look. Also, the horn has not gone off, should I run it longer - will it ever get a hot stream on the muffs. I would also like to know about the flushing port. The generic motor manual addresses flushing after salt water use. Can this port be used to run the motor like the muffs?

 

[Dhadley]

Re: 150 Johnson thermostat

Ive seen people run the motor on the flush port but I'd rather run mine on a flushette. The overboard stream wont get very hot. It reads incoming water.<br /><br />The large hole you talk about may be where the temp sender switch goes. There should be one in each head.

 

[Zaxxon II]

Re: 150 Johnson thermostat

Thanks D. I'd better take it to the lake before I try the thermostats. The brass plug is on the outside of the head between two head bolts. Both temp senders are inplace in the middle of the heads. I'm just wondering if the empty hole needs a brass bolt.