Thanks everyone! ‘84 115 TOP rebuild going!

[ianmoore]

Man!! I remember when I was prepping the boat for the season and found the dead C3. I told my wife that I was gonna try to fix the engine and there was a good chance it wasn’t gonna work…

I have never worked on an engine before, outside of simple rebuild of carbs and such. Opening up the block was a big deal to me.

I ended up getting all new pistons. New rings. Replaced a couple of reeds. Seals and such. I redid the fuel pump, carbs and water pump.

The motor is in the salt so there were some frozen parts. I ended up having to buy a midsection piece when too many of the bolts were frozen in them.

Almost all new bolts, and obviously new gaskets.

I am a touring musician so was busy quite a bit of the summer.. i would have a few days to work and then be gone for 3 weeks.. over and over. It was frustrating when I would have to order a part and wait, knowing I was gonna be gone again. And even with good notes, it was hard to keep everything together.

But I got her all back together, did a prep on muffs, and then put her in the water. I did the reccomended 6 atdc and 20btdc(18). I had the throttle linkage set to the mark, but ended up with idle stop in a bit, so idle now is slightly to right.
My bottom carb is showing a little fuel in the throat. Rechecked needle seats and floats. Everything is in spec. Not sure what that is yet, but keeping an eye on it.

But, here is the cool thing. The engine idles at 650-700 now. Before I had to keep it about 1000 or it would die in gear.
Smoother transition into rpm, but still keeping it low to break motor in.. so, havent tried WOT and/or make sure I am at proper rpm top end.

And, super happy to have the engine back together and wanted to say thanks to everyone who helped talk me through it

 

[ianmoore]

-Had an interesting thing with bottom carb. I took off the bowl, thinking something with the float had to be allowing some fuel in the throat. I couldn't find anything. I went ahead and took it apart. When i removed the needle seat, the crush washer was crushed at an angle. I tried reinserting a new one, and the same thing happened. There is something weird with the threads. I had a spare bowl, and replaced it. I'll report back if that solves the issue.

Question on timing- So, i timed to 6ATDC and 20(18BTDC). I was watching some vids on timing these old Mercs and a couple of people timed the first to around 0.
Obviously when I change the idle stop screw, i'm altering the throttle/butterfly relationship. There is some travel with the throttle before the butterflies open. Is this travel to account for possible variation in the idle screw adjustment? So, users could finetune their idle without going to deep into the engine?

Or would i be better off timing closer to 0 and keeping my throttle linkage mark lined up?

 

[jimmbo]

This is the Idle Stop Screw. The Carbs should be fully closed as the timing advances to the 6 degrees ATDC.