Johnson 130 Left Bank normal, right bank HOT!

[chopperguy]

Re: Johnson 130 Left Bank normal, right bank HOT!

id take the t-stats out completely and run her......just to see if cooling is an issue or if it is an OVERHEAT issue... I know they sound the same, but there is a difference.

then what happens would direct me what to look at next

plus id go back and reflush with some dish degergent squirted into the garden hose before you attach it to the motor

bob

OK with the t-stat out on the starboard bank it doesn't get hot. My infared thermometer reads 97 (starboard) after running a few minutes, and 130 on the port. Somehow the t-stat/relief valve is restricting water. Everything is clean, I've verified the t-stat is working and I removed the other side to verify i didn't put something together wrong. I'm pulling my hair out right now.

 

[chopperguy]

Re: Johnson 130 Left Bank normal, right bank HOT!

Today I purchased an infrared thermometer to see what's really going on. The starboard bank is maintaining 150F at idle. The port bank is at 111F. The generic manual I have says most Johnsons should be at 125-155F. So, it seems the left bank is running to cool. Another twist to the problem. Am I looking at this right? So now I have the opposite problem.

 

[fshrgy99]

Re: Johnson 130 Left Bank normal, right bank HOT!

are you running the motor on muffs or afloat? Have you run it at WOT and then checked the temperature differential?

 

[chopperguy]

Re: Johnson 130 Left Bank normal, right bank HOT!

running in a tub, going to try it in the water tomorrow.

 

[bob johnson]

Re: Johnson 130 Left Bank normal, right bank HOT!

know a few things...the thermostats dont normally open till about 140-150 degrees,

if you had temperature gauges on your heads you be able to see that. I have temp sender on EACH head and a GUAGE for EACH on my controls.

because carb issues can cause over heating , and friction problems can do the same independant of each head. even though the water cooling to each is equal

what are the temperatures of each head after running at idle for 15 minutes with the T-stats installed????

bascially trying to verify you actually had overheat issues...

id do a few tests to try and rule out blockage...hook up a flushing hose with the motor off at the flushing port just under the motor cover. remove one t-tstat and leave the cap of the t-stat housing off.. and see how much water is flowing out of that opening

then reverse that with the other head, closing up the previously open head and compare th amount of water flow out each opening..

if they are the same

id move to rebuilding the carbs to assure you dont have a lean condition..making sure I used new manifold gaskets as well!!!


good luck

bob

 

[chopperguy]

Re: Johnson 130 Left Bank normal, right bank HOT!

Ran an hour at high speed yesterday, kept it below 4000 rpm. Ran great as usual. Low speed the Right bank was 147F, Left bank was 130F. High speed Right bank was 119 and left bank the same. Temps are good, just don't know why the difference. I've seen other posts where people have the same problem. I'm wondering whether this outboard was this way all along (I've only had it a year). One comment I've seen made is the offset in height between the cylinder banks. The right bank is higher and if you had reduced water pressure from the impeller, could this cause the right bank to run hotter. However, according to the book it's temp is normal (Book says 125-155 at idle) I've already inspected the impeller and it looks fine. So I wonder if this difference is acceptable?