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Johnson 1989 Outboard Port Head Cooler than Starboard Head

mr_johnson

Regular Contributor
"I just took my boat/engine to

"I just took my boat/engine to a dealer to have it looked at.

They said the Port Head was cooler than the starboard head (too hot to touch) - implying the t/stats and/or release valves are not functioning properly.

I am about to remove the t/stat assy tomorrow and ask what I should be looking out for to address this apparent coolign problem?

BT - The alarm does not turn on.

Also, I need to know what size the head of the screw is that holds the t/stat assy onto powerhead. Can anyone advise please?

Attached file shows Item 26 (Screw).

Cameron
221513.jpg
"
 
"sounds like your on the right

"sounds like your on the right track with replacing the therms, sorry i dont know what size bolts are on your model.........if i were changing the therms i would go ahead with a new water pump also.

other than that you might try compressed air or a water hose in the therm holes to check for blockage."
 
"<center><table border=1><tr><

"<center><table border=1><tr><td>http://www.marineengine.com/discus/icons/mime_msword.gif""" align=left alt=""application/msword"">
[url=""][b]ThermoStat Housing Bolt.doc[/b][/url] (37.4 k)</td></tr></table></center>

Attached is a clearer picture of the bolt.

Thanks David."
 
"mine has "7/16 bolts hol

"mine has "7/16 bolts holding on my housing,mine looks just like your diagram but its a '79"
 
"OK Team,

Pulled the t/stat


"OK Team,

Pulled the t/stat assy and was very suprised to find/observe the t/stat port side was jammed and kept open by a fairly large sand particle.

Also the gasket area to one side of this t/stat was swollen with gap rock hard.

So, does this support the dealer's prognosis of port side head being cool while starboard head being too hot?

I have not yet tested the t/stats for function yet but will do.

With the t/stat presumably being open for so long, do i need to replace it?

Attached photos for your viewing...

And I am very keen to read your thoughts after this post.

221538.jpg


221539.jpg


221540.jpg
"
 
"sounds to me like the starboa

"sounds to me like the starboard side may be sticking closed while port is stuck open............probably a good thing you had a piece of sand in there or you might possibly be having a completely different conversation right now.

are you going to replace the water pump?

i would especially if youve picked up enough sand to keep your therm open.........if the housing is in good shape you can just replace the impeller. most people on here would probably say replace the whole thing, but its more of a judgment call when you can visually inspect it in person.

let us know how the therms test goes."
 
just buy the kits thermo kit /

just buy the kits thermo kit / water pump kit.
based on what i see you are going to need it.
the parts are not that much money.do you really want to reuse those old ones.
 
"<[img]"http://www.marineengin

"
221555.jpg
Air bleed holes"">
Within the circled area are two small holes. Make sure that they are not obstructed. If obstructed it will cause an air lock leading to overheating."
 
"Thanks guys.

Will go ahead


"Thanks guys.

Will go ahead and buy new t/stats, water pump.

Did the t/stat test - both opened up but the port one did not close back.

Damn. I replaced these items 12 months ago too. Is this what boat is all about I guess?

How often do stuck t/stats occur?"
 
flushing will help prolong thi

flushing will help prolong this.
you should get more than 12 mos out of a new set.
my guess is it sits in salt for extended periods of time
 
"Thansk Guys.

Attached belo


"Thansk Guys.

Attached below is another photo showing the housing - clean up somewhat - and shows only one hole - not two holes.

Should I be drilling another hole or what?

Also, those bolts came out pretty well - shoudl I still apply anti-sieze?

Cam

221573.jpg
"
 
"i dont tear those down every

"i dont tear those down every day bub........but,it kinda looks that way...just make sure all passages are clean..repl thermo's and pres rel valves and kick it in the ass."
 
Thanks JWB

Should I drill


Thanks JWB

Should I drill more holes in that rubber housing in the rectangular area I highlighted in that photo?

I am confused - this housing is the genuine Johnson part from BRP index. Why did it come iwht 1 hole when it should have 2?

Cam
 
thanks jwb - why anti-sieze th

thanks jwb - why anti-sieze the new gaskets?

I thought anti-sieze should only be used on bolts?

Cam
 
"A thorough flush with clean f

"A thorough flush with clean fresh water after use will keep the motor clean and not prone to plugging up. A must in Salt Water but I've found it's also useful when running in nasty fresh water. I've seen it all flushed out of my motors (sand, mud, debris, vegatation, etc.)
Bill"
 
"Cam, Check the other side of

"Cam, Check the other side of that plastic housing. I seem to remember asking myself the same question when I did the stat's on my motor. If I remember correctly, there is a small notched out area on one side of the housing. That allows the single hole to serve both sides of the system.

Dan"
 
"Thanks Dcramer -

That pla


"Thanks Dcramer -

That plastic housing is now stuck onto external housing (as per pic) and I am loathe to rip it off. DO u think I have put this housing on the wrong way ? If so, I should take it off.

Cam"
 
Probably only 'hanging&#39

Probably only 'hanging' in the gasket.
Take it all apart and get it cleaned up properly.
Housing is the correct way.
 
"the gasket is still on the be

"the gasket is still on the before photo,
it looks a little cleaner in the after.
when i did mine i used a dremmel with a wire
brush and blasted the inside clean,it looked like new."
 
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