1990 merc 115 overheat? help!

[bmal]

What caused my problem? Had my 1990 merc 115 2+2 out the other day and clogged the tell tale with mud (lake low). I motored back to the dock, checking the powerhead on the way and it remained cool to the touch.

Cleaned the hose when I got home and it pumped fine, motor ran fine. While I was at it I decided to de-carb the cylinders and replace the plugs. I heated the motor for 5-10 minutes on muffs, shut it off, and took out the plugs. The top two plugs, which run while idling, came out harder than usual, and took threads out with it.

Now I have two stripped holes. Did the motor overheat and mildly seize the cylinder threads to the plug, or, should I have waited to remove the plugs after warming the engine?

I tried to rethread but not enough metal. Time-sert, keen-sert, or new block?

Any help is appreciated.

 

[yorkserv]

Re: 1990 merc 115 overheat? help!

There is a thread on here about something similar someone stripped the heads with the plug

Click here http://forums.iboats.com/showthread.php?t=195990&highlight=stripped+spark+plug

good luck i recommend putting neverseize on thread

 

[bmal]

Re: 1990 merc 115 overheat? help!

My question is more...did running it for ten minutes, then pull the plugs right away make it hot enough to ruin the cylinder threads...or was it probably running it with the pee hole plugged, even though it felt cool to the touch.

In addition with the tell tale plugged, does water still circulate through the motor?

 

[bmal]

Re: 1990 merc 115 overheat? help!

I'm looking more for an opinion, not a definite answer. I know whats wrong and what to do...but why did it happen? How fast do these things overheat. After running, how long to wait before pulling plugs?

thanks

 

[Chris Cole]

Re: 1990 merc 115 overheat? help!

bmal,

My tell tale was showing just fine and had run my motor for approximately 15 minutes. I also had a torque wrench and didn't have my spark plug torqued more than 20 lb-ft.

I took my spark plugs out twice while running my motor as mentioned above. The second time I pulled the plug I noticed thread shards on my spark plugs.

As far as how to correct the problem, I have been told an insert will make metal shavings that will fall in the cylinder .

My conclusion was not to take the spark plugs out when the block was even warm!

 

[bmal]

Re: 1990 merc 115 overheat? help!

Appreciate the reply. I am newer to outboards, and didn't think it would be a issue since compression tests and de-carb are to done with a warm engine.

 

[tashasdaddy]

Re: 1990 merc 115 overheat? help!

if you pick up enough water to clog the tale tell it's in the engine also. the tt is the last point in the motor to get water, when the tstat opens. it allows water to circulate.

 

[starcar331]

Re: 1990 merc 115 overheat? help!

What caused my problem? Had my 1990 merc 115 2+2 out the other day and clogged the tell tale with mud (lake low). I motored back to the dock, checking the powerhead on the way and it remained cool to the touch.

Cleaned the hose when I got home and it pumped fine, motor ran fine. While I was at it I decided to de-carb the cylinders and replace the plugs. I heated the motor for 5-10 minutes on muffs, shut it off, and took out the plugs. The top two plugs, which run while idling, came out harder than usual, and took threads out with it.

Now I have two stripped holes. Did the motor overheat and mildly seize the cylinder threads to the plug, or, should I have waited to remove the plugs after warming the engine?

I tried to rethread but not enough metal. Time-sert, keen-sert, or new block?

Any help is appreciated.

hi, a lot of time the threads will corode, you can pick up a 14mm helicoil kit
it useualy comes with a tap and new threads to repair the problem some of the local parts stores carry the kits
hope this helps

 

[starcar331]

Re: 1990 merc 115 overheat? help!

What caused my problem? Had my 1990 merc 115 2+2 out the other day and clogged the tell tale with mud (lake low). I motored back to the dock, checking the powerhead on the way and it remained cool to the touch.

Cleaned the hose when I got home and it pumped fine, motor ran fine. While I was at it I decided to de-carb the cylinders and replace the plugs. I heated the motor for 5-10 minutes on muffs, shut it off, and took out the plugs. The top two plugs, which run while idling, came out harder than usual, and took threads out with it.

Now I have two stripped holes. Did the motor overheat and mildly seize the cylinder threads to the plug, or, should I have waited to remove the plugs after warming the engine?

I tried to rethread but not enough metal. Time-sert, keen-sert, or new block?

Any help is appreciated.

hi, a lot of time the threads will corode, you can pick up a 14mm helicoil kit
it useualy comes with a tap and new threads to repair the problem some of the local parts stores carry the kits oh and it is better to let the engine cool down before changing the plugs
hope this helps

 

[bmal]

Re: 1990 merc 115 overheat? help!

Thanks...I thought about it seizing over the winter, but it was only the top two which it idles on. I had fogging oil sprayed in cylinders, wouldn't that prevent it. I would guess some was on the threads.