1980 Johnson 100 V4 Crossflow cooling questions

cdods

Cadet
Joined
Jul 7, 2012
Messages
14
Just taken over maintaining the family boat & trying to get it running well again. Now that all cylinders are firing well, I'm on to cooling. Two issues and questions:

1) Running on rabbit ears, the right cylinder bank got very hot quickly, but left stayed cool to touch. I've verified are all running, so it sounds like a cooling issue. As I don't believe the thermostats or impellor have every been replaced I'm going to do both. But before I do that, can anyone confirm that running on rabbit ears at idle I shouldn't be seeing a significant difference in temp between the two cylinder banks? Tell tale is strong, but hardly warmer than the incoming water.

2)I noticed a small amount of water leak from around the bottom 2 or bolts on the right side of exhaust manifold cover. Essentially a slow continuous drip. Is this likely more than just a bad gasket?

3) I know - I said two questions, but I'm going to sneak in a third. There is obviously fuel leaking from the right side of the carbs. The whole right side around the carbs is oily, but it's not obvious where it's coming from. It might be from the bowl gaskets, but if so, I'm not sure how it would work it's way up to the top throttle shaft and synchronization linkage which are wet with fuel/oil. Are there any common leaks I should be looking for?

Thanks
 

Bosunsmate

Admiral
Joined
Apr 7, 2012
Messages
6,135
thatd be a no, no and no
clean the carbs then prime the fuel bulb and watch for it
 

SparkieBoat

Captain
Joined
Aug 17, 2009
Messages
3,643
replace the thermostats, replace the leaking gasket, and pump the bulb hard to find your leak.
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
You may also have some bad water deflectors in the block.
 

cdods

Cadet
Joined
Jul 7, 2012
Messages
14
Thanks for the responses. I guess I have my work cut out for me this weekend. Hopefully will be boating soon...
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
When you tear into the thermostat housing, check out the plastic "valve body." There are two pinholes in it. Make sure they both are clear (open) or the engine will overheat on the plugged side.
 
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