Overheating OMC TubroJet 115

[toddperk]

hello all,

I purchased a '94 SeaSwirl with a TubroJet 115. I worked fine until ..... I winterized it last fall. Not having the special fitting, i disconnected one of the cooling line and used compressed air to blow the water out. then, with a hand pump, pumped antifreeze in after starting the engine. within a minute or so of doing this the high temp alarm triggered and I turned the engine off.

This spring I reconnected the house I removed and dropped it in the water. the engine started and ran fine. The coolant lines on top of the head had some water, but not much, flowing to the muffler. I would say about 50/50 air and water. (is that enough flow? and should there be air in it?) After 3-5 minutes the high temp alarm went off. I sprinkled a few drops (yes, just a few) on the head and they immediately boiled off so I know the heads where really hot.

Now, my question, what should I check? what should I do to fix the problem? I heard that I may have blown out an exhaust to water gasket with the air pressure winterizing?

thank you in advance

 

[HT32BSX115]

hello all,

I purchased a '94 SeaSwirl with a TubroJet 115. I worked fine until ..... I winterized it last fall. Not having the special fitting, i disconnected one of the cooling line and used compressed air to blow the water out. then, with a hand pump, pumped antifreeze in after starting the engine. within a minute or so of doing this the high temp alarm triggered and I turned the engine off.

This spring I reconnected the house I removed and dropped it in the water. the engine started and ran fine. The coolant lines on top of the head had some water, but not much, flowing to the muffler. I would say about 50/50 air and water. (is that enough flow? and should there be air in it?) After 3-5 minutes the high temp alarm went off. I sprinkled a few drops (yes, just a few) on the head and they immediately boiled off so I know the heads where really hot.

Now, my question, what should I check? what should I do to fix the problem? I heard that I may have blown out an exhaust to water gasket with the air pressure winterizing?

thank you in advance

Howdy,

Welcome aboard!

I am not at all familiar with any of the OMC jet drives. But I did do a little search and found the following:
https://forums.iboats.com/forum/eng...s/86028-omc-turbojet-115-over-heating-problem

Evidently because the Turbojet is dependent on it's own (JET) pump for cooling water, it's VERY sensitive to idle RPM.

Also, there's other stuff that can affect it.

A google search found the following......

[FONT=Verdana, Arial][FONT=Verdana, Arial]"When out of water runs fine with hose. Put Boat in water and she overheats. Water pump?"
////////////////////////////////////////////
Not the water pump. The entire jet assembly is the water pump on a Turbojet. There is no rubber impeller as an Outboard would have. The turbojet uses a hole located at 12 o'clock in the mid-section of the impeller assembly to collect pressurized water for cooling purposes. If you remove the rear funnel portion which compresses the water into a jet (four 6mm allen head bolts), you will find a large flat head screw. Under that screw is a spring and a ball valve. The intent is that the ball valve opens at 20psi to vent excess pressure from the cooling system. However, it is possible to get a piece of debris stuffed into that ball valve and vent the minor pressure available at idle. (I see 0-4psi at idle on my water pressure gauge). It would not take much loss to equal zero cooling water pressure.[/FONT][/FONT]
[FONT=Verdana, Arial][FONT=Verdana, Arial]I mention this ball valve and the possibility of getting something stuck in it because it is in the portion of the impeller housing you "pull back" to install the OMC garden hose adapter for flushing. Ordinarily, you would never know if it is leaking pressure or not. There is no effective way of testing the valve. [/FONT][/FONT]

[FONT=Verdana, Arial][FONT=Verdana, Arial]If for some reason, your engine ingested a piece of debris, and that piece of debris was small enough to go into the cooling water pickup hole, it could probably clog something enough to prevent adequate cooling. In theory, everything is supposed to pass through there and get hung up in your strainer, but there is always a possibility you got a Zebra mussel or something odd plugging up the hole. Run water backward through the impeller housing cooling water passage. See if something comes out... [/FONT][/FONT]

I hope this helps.

There's not a lot of places that will work on 25 year old equipment from a company that has been out of business for more than 20 years.....

Maybe this thread might be better served in the OMC outboard section......


Cheers,

Rick

 

[toddperk]

thank you Rick.