84 Merc 115 acting up

[procraft89]

I just rebuilt the carbs on this thing, took it out friday for a test. It ran ok, nothing special but then I was going about half throttle down the lake friday night to watch fireworks it suddenly quit.

Now, it will run with the warm up lever at least 1/3 up but will NOT idle. It also will not run with a load. If I drop the warm up lever fast and hit the throttle it sputters and dies.

The prop moves freely when in neutral and I can turn it by hand with it in gear and I hear the motor turn over.

any ideas?

 

[procraft89]

Re: 84 Merc 115 acting up

Yesterday I did notice a small round cap on the bottom two carbs, it looks like it is held in with some kind of adhesive. The cap is missing from the top one but is there on the bottom two.

I remember taking that cap out, then seeing there wasnt much behind there so cleaning it (only on one). I am pretty sure I put a replacement back in there, if it fell out could that be the problem? what kind of adhesive holds those in....loctite, sleeve retainer???

 

[procraft89]

Re: 84 Merc 115 acting up

nobody has any ideas?

 

[jethrosixxx]

Re: 84 Merc 115 acting up

I'm not familiar with that motor but you may have clogged/fouled pilot (low idle) jets.

 

[crazyclam]

Re: 84 Merc 115 acting up

Sounds like its definately in your carbs.....Either a clogged jet.....bad gas....piece of crap somehwere in the carb.....take them apart and make sure you have all your pieces that will ruin your day...clean out each jet carb cleaner and air.....will be better in long run take pics when apart for reference..

 

[procraft89]

Re: 84 Merc 115 acting up

I just rebuilt them, this was actually the maiden voyage. The tank is full of Amoco 93 octane.

I am really wondering about that plug on the top carb, it looks like a freeze plug and has a couple orifices behind it. I removed it off of one of the carbs and now that one is missing. It looked like some kind of glue was holding them in place, what kind of adhesive is that? Will not having it on there possibly make it run lean? I am thinking that if it will, that will explain why it will run with the warmup lever up...its running on the main jet but one carb is too lean on the pilot.

 

[procraft89]

Re: 84 Merc 115 acting up

I just rebuilt them, this was actually the maiden voyage. The tank is full of Amoco 93 octane.

I am really wondering about that plug on the top carb, it looks like a freeze plug and has a couple orifices behind it. I removed it off of one of the carbs and now that one is missing. It looked like some kind of glue was holding them in place, what kind of adhesive is that? Will not having it on there possibly make it run lean? I am thinking that if it will, that will explain why it will run with the warmup lever up...its running on the main jet but one carb is too lean on the pilot.

 

[76canaventure]

Re: 84 Merc 115 acting up

Hi there!
It sounds like you are missing a welch plug. Not having it in place will make it run horribly. They are tapped into place on reassembly. Place it in the hole convex side up and tap flat. I have never put any kind of sealer on them before. If you can do it safely, put your finger over the hole and start it up, it should run like normal. Hopefully you still have 1 or 2 left over from your previous rebuild.
Best Regards

 

[procraft89]

Re: 84 Merc 115 acting up

Hi there!
It sounds like you are missing a welch plug. Not having it in place will make it run horribly. They are tapped into place on reassembly. Place it in the hole convex side up and tap flat. I have never put any kind of sealer on them before. If you can do it safely, put your finger over the hole and start it up, it should run like normal. Hopefully you still have 1 or 2 left over from your previous rebuild.
Best Regards

THAT was the confirmation I was looking for. Today I went out and found the one I had knocked out and 2 shiny new ones. The original ones had some kind of glue in them, I will figure out what to seal them in with and go with that.

You just made my day!