metriccrescentwrench
Commander
- Joined
- Oct 22, 2007
- Messages
- 2,598
I test ran a new-to-me 1990 Johnson 200 for the first time this week. After 10 or 15 minutes the overheat alarm sounded, so I immediately idled back to the dock and put the boat on the trailer (the alarm turned off after a couple minutes of idling). This engine has a brand new water pump, and water pressure was good the entire time. I'll go ahead and replace both thermostats, but have a couple other questions.
Somewhere along the way the aspirator was removed, and the water line that went to the aspirator from the starboard thermostat cover was just plugged with a bolt. Is that an acceptable way to disable the aspirator?
I noticed that the vent hole in one of the thermostat diaphragms was plugged up with crud. My feeble little brain can't figure out what the vent holes (and interconnecting hose) are needed for - unless it's to balance water pressure between the two sides. Could this have caused the overheating?
Finally, I believe I remember reading something to the effect that thermostats on 90 and older V6's (they resemble a salt shaker) should be replaced with thermostats from '91. Is that correct?
thanks
Somewhere along the way the aspirator was removed, and the water line that went to the aspirator from the starboard thermostat cover was just plugged with a bolt. Is that an acceptable way to disable the aspirator?
I noticed that the vent hole in one of the thermostat diaphragms was plugged up with crud. My feeble little brain can't figure out what the vent holes (and interconnecting hose) are needed for - unless it's to balance water pressure between the two sides. Could this have caused the overheating?
Finally, I believe I remember reading something to the effect that thermostats on 90 and older V6's (they resemble a salt shaker) should be replaced with thermostats from '91. Is that correct?
thanks