johnson 125 1971 port to starboard temp

[brickster]

Is it common for a 1971- 125 to run hotter to touch on the starboard side? Seems to be the same with or without thermostat. Or may i be looking at some blockage? Thanks for any help.

 

[racerone]

Re: johnson 125 1971 port to starboard temp

Should be the same.----Post pictures of the powerhead.

 

[boobie]

Re: johnson 125 1971 port to starboard temp

Have you checked the temps with a temp gun ??

 

[brickster]

Re: johnson 125 1971 port to starboard temp

Havn't used a temp gun yet but it is very noticeable by touch between cylinder 2 cooler and cylinder 1 hotter. Removed vernatherm, check valve, vernatherm valve and springs and ran it on a hose, it was much cooler but still noticeable. Checked vernatherm, opened at 160 degrees which is much hotter than a new one that claims opens at 105 so a new vernatherm is on it's way. Lower unit is coming off again so i will check water tube connections and since thermostat will be opened might try compressed air and see how it blows through to check for any obstruction, or maybe hose water, what would you suggest?

 

[emdsapmgr]

Re: johnson 125 1971 port to starboard temp

Those early crossflows with the single vernatherm should run cooler at idle. Maybe 110 to 115-the manual may say as much as 130. 160, while not an overheat-is still considered too warm for normal idling. Good call to replace the vernatherm. If you still have a significant temp variance between heads, you might want to remove the cyl head covers (not the whole head) for a visual inspection. Sometimes these head passages get restricted (even filled with sand, salt, etc) and that could restrict water flow in one head.

 

[brickster]

Re: johnson 125 1971 port to starboard temp

Removed cyl head covers and am very confused at the heavy buildup of what appears to be hardened white sand in the recessed portions of the cyl head cover, not sure how it could get past the cover gasket. Connected hose to water tubes with covers off and water seems to be running fine. Any Idea why the backs of the covers have figure 8 shaped recesses?

 

[emdsapmgr]

Re: johnson 125 1971 port to starboard temp

You don't say where this engine has run it's life. Depending on where it's been run, it would be salt deposits or even some residue, including sand. Whatever buildup you see in the heads is also inside the block and inside the main water galley between both banks of the heads. (under the water passage cover.)

 

[brickster]

Re: johnson 125 1971 port to starboard temp

this is a lake michigan motor and the buildup was not in the heads, they were completely clean, the buildup was in the recesses of the cylinder covers whitch seems impossible, not sure how the sand could get past the gasket, and i say sand because i tasted it.