erratic tach and water passage blockage

[bob johnson]

so I just fired the boat up after not running since feb...started right up!, I was going to de carb the motor and I let her warm up at 1100 rpms...if I tried to push it to 1200 the tach died. but the motor ran fine...I sparayed the decarb and while I am letting it smoke out I noticed the tach would die off and restart...but the motor never skipped a beat....

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is the rectifier dying?

second question is that one bank of the motor is always hotter than the other...same side all the time...one head is 170 degrees the other is 120 degrees....it sometimes approaches 185 on hot days with a warm body of water at idle rpms.... once I raies the rpm and the water pressure rises to about 20lbs the temps cool off to the very low 100s.

so it insufficient water at idle, when I took the muffs off I plugged the hose right into the flushing port, and even squirted a little dish soap in the port and I ran the water for 10 minutes. the one normal bank got cool very quickly the other was still very warm to the touch!.. eventually the one head was forming condensation there was so much cold water running through it. the other side was still warm!!

where could this blockage be??? is there a known place that can clog??

1995 Johnson 115 ocean runner....60 degree looper OIS motor

thanks
bob

 

[metriccrescentwrench]

is the rectifier dying?

More than likely. Chances are your battery isn't being charged properly either.

where could this blockage be??? is there a known place that can clog??

I'd start with the thermostats. While you have 'em out you can look into the cooling passages as best as you can and see if there are any signs of corrosion or other gunk. If it looks bad then pull the heads to inspect the cooling passages.

 

[bob johnson]

More than likely. Chances are your battery isn't being charged properly either.




I'd start with the thermostats. While you have 'em out you can look into the cooling passages as best as you can and see if there are any signs of corrosion or other gunk. If it looks bad then pull the heads to inspect the cooling passages.

yeah I have had this issue for 5 or 6 years... and in that time I have changed out the t-stats three or four times...no change...plus I have had the heads off and looked at the passages..the heads are clear....not sure of the block though

bob