1984 Johnson J6RCRM - found this hole under the exhaust cover - advice?

[Moxie]

I purchased this motor with a small boat in June of 2011. I used it on a different boat for smaller lakes and ponds and the motor never did seem to have the power I thought it should have. Nevertheless, I winterized it and stored it indoors over the winter. Pulled it back out a couple of weeks go, wouldn't fire. Removed the carb, cleaned the jets, new plugs, etc. etc. you know the drill.... Fired first pull.

In the test tank it still didn't seem to be running properly and I was suspecting something electrical/ignition. pulled it back inside on the tan and really started to break it down some more. I found the motor in general to be "unclean" but some car mom build-up was expected.

1.) The thermostat showed corrosion but it cleaned up and the spring still works. I am most likely going to replace it if I am going to fix the motor along with the impeller although the impeller is fairly new.

2.) Two bolts snapped when removing the exhaust cover due to corrosion while removing the exhaust cover. That was a red flag.

3.) Upon looking under the ex. cover, I found what is shown in the photo. I am guessing the motor was probably overheating. Is this something that can be repaired with JB Weld?

The hole looks like it was caused by corrosion but I'm not 100% positive.

 

[F_R]

Re: 1984 Johnson J6RCRM - found this hole under the exhaust cover - advice?

I see the hole, but what am I looking at? Is it the exhaust housing or the cylinder block that is eaten away---or both? Either way, JB Weld??? Not in this lifetime. Besides. the motor probably is toast.

 

[Chinewalker]

Re: 1984 Johnson J6RCRM - found this hole under the exhaust cover - advice?

Looks like a corroded hole through the exhaust tuner pipe. Only fix is to have it either welded, or replace the tuner... Several on eBay right now...

 

[Moxie]

Re: 1984 Johnson J6RCRM - found this hole under the exhaust cover - advice?

I'm adding a few more photos to give you a better idea as to the location of the hole. I'm still tearing the motor down at this point and will take some additional photos. Thanks for your help. I don't know much about this motor but I'm about to get a crash course.

 

[F_R]

Re: 1984 Johnson J6RCRM - found this hole under the exhaust cover - advice?

Still looks to me like there is a big hunk missing out of the cylinder block, as well as the exhaust tube. I may be wrong.

 

[Chinewalker]

Re: 1984 Johnson J6RCRM - found this hole under the exhaust cover - advice?

Looks like you can get some vice-grips on the bolt stubs sticking out from the block. Some heat, penetrating oil patience and more heat MAY loosen them up without breaking off flush.

 

[Moxie]

Re: 1984 Johnson J6RCRM - found this hole under the exhaust cover - advice?

I agree on the vice grips. Those are in the plans for sure. I've been hitting them with the oil.

Chinewalker: Could you give me some more info on the "Tuner Pipe"? I just went through the parts lists and cannot find a part by that name. Behind that exhaust cover is basically an empty cavity.

 

[F_R]

Re: 1984 Johnson J6RCRM - found this hole under the exhaust cover - advice?

391685 Exhaust Tube, inner. Long tube sticking down into the midsection housing.

 

[Moxie]

Re: 1984 Johnson J6RCRM - found this hole under the exhaust cover - advice?

391685 Exhaust Tube, inner. Long tube sticking down into the midsection housing.

Thank you Chinewalker -- I can actually see the inner wall of the exhaust housing through the hole so you might be right on that. If it turns out to be the case, what sort of problems would something like that cause. Does it basically just amount to an exhaust leak?

 

[Chinewalker]

Re: 1984 Johnson J6RCRM - found this hole under the exhaust cover - advice?

Makes the motor run louder. Might lose some power due to improper exhaust scavenging/backpressure. May allow water into the cylinders as the water exits around the exhaust tube. I would replace it...

 

[Moxie]

Re: 1984 Johnson J6RCRM - found this hole under the exhaust cover - advice?

I've got the motor torn down and those bolts did come out with some heat / oil. It does need some cleaning, no doubt about that. As for that hole.... Doe anybody know if there was a hole there to begin with, just smaller? I've seen some exhaust tubes with a "relief" hole but am not sure if this motor had one or not. I've been looking for a used one online but can't seem to find a match. I'm thinking about attempting a repair even if it's temporary, just not sure what the best approach would be. I was even considering glassing it shut with some strong roving.