OMC TurboJet 115 Engine overheating

[BinzlBrew]

Does anyone have any advise for me. I purchased my father-in-law's boat after sitting in his garage for3 years. I had the fuel polished (cleaned) along with fuel tank cleaned. Bought new batteries, connected water hose to hose intake and started engine. No problems. It's running great. Launched boat for first time and within 5 minutes of running engine, siren sounds to warn for overheating. Let it cool down (about 20 mins), started engine and siren sounds again within 2 minutes. I took it home and it ran for 20 minutes without a problem. I disconnected all hoses and ran water in both directions to check for clogged hoses or obstructions and I didn't find any. I'm guessing that it's a cooling intake problem but that's as much as I can deduct. Engine is an OMC 115 TurboJet drive. Any ideas or solutions?

 

[SKEETR]

Re: OMC TurboJet 115 Engine overheating

Split the jet drive to access the pressure relief valve. Inspect the intake passages for debris. Next step would be on to the thermostat assembly. If you are going to access the thermostats just order some new ones so they can be replaced. It is a pain to do so no sense in second guessing. Another place they get plugged up is in the heads themselves but I would check the above first.

 

[BinzlBrew]

Re: OMC TurboJet 115 Engine overheating

Thank you Skeetr. I will try that as soon as I figure some things out and recover from aggravating some herniations in my back. Excuse my ignorance but what exactly do you mean by "split the jet drive"? I was prepared to take the impeller housing off and also remove the intake plates off the bottom of the boat but I felt as if the allen bolts were gonna snap on me.

 

[SKEETR]

Re: OMC TurboJet 115 Engine overheating

You are actually going to split the impeller housing. Remove the four bolts of the nozzle assembly and with a thin blade putty knife or whatever cut the silicone sealing the part together. The nozzle also covers a 1/2" slotted cap. In these is a spring and ball used to regulate 20psi. Check there for debris pushing a wire through to make sure. Replace with a thin coating of silicone. With the impeller housing off you should be able to see down to the top of the intake grate so don't snap any bolts if you don't have to.

 

[BinzlBrew]

Re: OMC TurboJet 115 Engine overheating

Thanks Skeetr. I was planning to take impeller housing off and now feel better about it. Thanks again. I hope to get on it by Thursday.

 

[BinzlBrew]

Re: OMC TurboJet 115 Engine overheating

Hi Skeeter. Removed impeller housing all seems good except that I could not remove 1/2' slotted cap. Tried with all my might and chemicals only to strip slot. Pushed a long thin screwdriver from opposite end and seems like ball bearing moves. Ran engine with hose connection and shoots water out of every orifice. put everything back together, put boat in the water and siren sounded in 3 mins. Gonna buy screw removal kit to clean out properly and replace slotted cap. First need to order slotted cap (hopefully I can find it) so that I can replace it. Could it be the thermostat? maybe it doesn't overheat with water hose due to higher pressure of city water source?