It Overheated On Me, Now What

[flyingd]

Need some advice. Was out with the boat, it is an 1969 18' Chieftain with the 120 I/O mercruiser, and it overheated good/bad on me. The week before no problem.

Got it home and now that it was cooled off I tried starting it; it started up fine and idled good. So, after some talk with the marina, I took the out-drive off and took out the pump......it was toast from the heat. I also took off the exhaust riser to check it and found that the water jacket had corroded through, so that is toast too.

My question is, what else should I be looking at before I buy those parts and stick it back together hoping that it will run cool. It had been running good up until that day.

Thanks in advance

 

[Fun Times]

Hi there, sorry for the delay with your topic.

If you haven't already done so, one thing you may want to do is watch the video linked below made by forum member achris. Within the first 4 minutes he talks about the gasket and seal found on the upper drive shaft housing that may have went bad on you during the over heat. You may need a new water pocket cover, item # 3, http://www.mercruiserparts.com/Show...RIVE+SHAFT+HOUSING+ASSEMBLY+AND+GEAR+ASSEMBLY

https://www.youtube.com/watch?v=ev4NVyyyIkU&feature=youtu.be

 

[Eric 3.7LX Alpha 1]

Since you have overheated, buy yourself the complete water impeller kit including the upper and lower housings and not just the impeller. How old was the existing one that failed?

 

[flyingd]

3 or 4 years I think I bought it 3 - 4 years ago

 

[thumpar]

It should be changed at least every other year. The 120 is pretty stout. I would only worry about the shutters and other exhaust rubber parts. How long and how high was it overheating?

 

[flyingd]

It ran about 90 secs on red. When I got to the dock there was smoke coming from the cowling. I turned it off; it did not quit on me. I would have let myself be towed in but there was no one around. The next day I tried starting it up to see if there was any knocking and it started right up and ran just fine.

What are the shutters?

 

[alldodge]

It ran about 90 secs on red. When I got to the dock there was smoke coming from the cowling. I turned it off; it did not quit on me. I would have let myself be towed in but there was no one around. The next day I tried starting it up to see if there was any knocking and it started right up and ran just fine.

What are the shutters?

If you have shutters, they will be on the top of the exhaust pipe. There would be a rubber exhaust tube going from the exhaust manifold to the pipe. You may have what is called a check valve system. All depends on what you have.

When you replaced the impeller did you account for all the pieces? If not, check the thermostat housing to see if any of the pieces from the old impeller made it there.

 

[flyingd]

I did check the thermostat housing for pieces and did not find any; the impeller was not torn up or losing pieces of itself.

Are there diagrams that I can look at to see what you were talking about concerning the shutter and/or the check valve system?

 

[alldodge]

Here is a link to the check valve but it may, or may not be your setup. I don't know your engine serial number

http://www.mercruiserparts.com/Show...D+ASSEM+(CAST+IRON)(SERIAL+#+1725593-2046624)

 

[thumpar]

Check the rubber parts in the exhaust system. That smoke was the rubber being too hot.

 

[flyingd]

All Dodge
That picture does not show my setup. Mine, at the end of the exhaust manifold, the mounting surface is facing up and the riser looks more like a uturn/camel hump.
odd description I know.

 

[Bondo]

All Dodge
That picture does not show my setup. Mine, at the end of the exhaust manifold, the mounting surface is facing up and the riser looks more like a uturn/camel hump.
odd description I know.

Ayuh,.... Can ya post the Serial number of the motor,..?? AllDodge is runnin' blind, tryin' to help ya,....

 

[flyingd]

The casting number is 3915983, the stamped number is V09266BC. Thanks for all the help