You may have a thermostat assembly partially obstructed or stuck due to age, dirt or other debris. T-stats should be serviced annually and a running temperature check of your motor would be a good idea. Looper V-4's usually idle at 140 degrees and at W.O.T. should not exceed 160, although they normally run cooler at W.O.T. than at idle. Have it checked out soon - normally port & starboard banks run within a few degrees of each other.<br /><br />-John
A restriction in the cooling system anywhere would cause this,as will an impeller, or thermostat failure.<br />How old are the impellers in you engines?
Might want to inspect the relief valves as well. If they get corroded and stick open, its the same as having a open thermostat...<br /><br />Good luck!
I've replaced the water pump 15psi on gage.<br />I have the white Thermostats one doesn't seem to be closing completely. What is the part # for the black Thermostats? Were they and upgrade or something?
The black thermostats replaced the white ones about 10 years ago. They are shorter and have a rounded tip, the white ones were longer and could "stick" in the rubber seat.<br /><br />Remove your rubber seats, clean out any buildup behind them, and install new ones with the t'stats. Replace the rubber diaphragms also.
The black ones are 434137. Actually, I really like the set up on the 1993's and newer. You need two of each of;<br />333967 Cover<br />329830 Gasket<br />434137 Thermostat Assy (same)<br />320880 Seat<br />330273 Cup<br /><br />Now you can do away with the throttle control by-pass valve and all it's hoses. It's the valve located to the rear of the throttle arm with all the hoses. It's much cleaner looking and works better.<br /><br />Good luck!
Good morning<br /><br />Just wanted to say thanks to every one for the information. I'm heading out to the marina to see what parts I can pickup. If they have the parts to retro fit to 1993 setup I may try that.
Ha Dhadley<br /><br />I made it by the marina to pickup the cooling parts. Their installed but there wasn't time to test the engine today. Asked about swapping out the covers to delete the by-pass value and the guy goes super sonic on me. Tells me the parts won't work on my engine and wouldn't even lookup the cover part number so I could take a look. Did get the newer Thermostat Assy's though. Will look around to see if I can round up the parts for the swap some other place.<br /><br />Thanks
I love it! That's too funny. Maybe he was afraid he might learn something. <br /><br />I fooled around with the cooling on my V4 race motor and ended up with the spring set up so I could eliminate the hoses. At the time I had to use the 70 HP set up because the V4's were produced like yours. At the next race one of the OMC reps (a very close friend) told me it wouldn't work. The new models came out a few months later and guess what? No hoses and the spring deal on the thermostst! I called him to rub it in and if I remember correctly he mumbled something and hung up. At the next race his motor was like that. <br /><br />Ain't this fun?
BTW -- When you pulled the white assy out of the starboard head, was it hanging up in the rubber?<br /><br />Forgot to ask before. Sorry.<br /><br />Good luck!
Ya I had to pull the starboard side out. the other thing was that the vernatherm in the port side was longer than the one in the starboard side by about 1/32 so it moved around in the housing where as the one in the starboard side seat down tight in the housing.
I'm sure you'll find that was the problem. And I'm glad we had a little fun along the way. <br /><br />If you have trouble getting the rest of the pieces, let me know. I have a buddy who owns the local Evinrude shop. I'm sure he would be glad to get you the parts.<br /><br />Good luck!
