1977 115HP Carb adjustment? Going from 6,000' to 1,600' fishing trip

[DAaker]

What to do??? I'm going from Colorado Springs to Lake Oahe SD on a fishing trip. Anyone have any quick and/or easy solutions? You all probably know that the 115 HP is a carb fitted L6.

[daveswaves]

What to do??? I'm going from Colorado Springs to Lake Oahe SD on a fishing trip. Anyone have any quick and/or easy solutions? You all probably know that the 115 HP is a carb fitted L6.

You probably have .068 jets installed now, for the higher altitude. You will have to change them to .072. There is no easy solution.

[DAaker]

Thanks! In my Seloc Vol 3 I'm noticing on page 4-19 that the main fuel jet on the type A carb is on the base of each carb in the front. I checked my motor and it seems that I can reach the top 2 carbs bolts easily but the bottom has a bracket that might be a problem. If I do get them out, is all that's necessary is to change the main fuel jet, #10 in the diagram? Finally, do you think this is doable by a novice?

[buzzm19]

I just did mine 78 115 same motor, I took out the four bolts on the front plate and made things a lot easier. Make sure you disconnect the battery first, then I could move the plate to the side and didn't have to disconnect any wires, if you haven't changed them before be prepared as they can be very tight. Buz

[daveswaves]

Thanks! In my Seloc Vol 3 I'm noticing on page 4-19 that the main fuel jet on the type A carb is on the base of each carb in the front. I checked my motor and it seems that I can reach the top 2 carbs bolts easily but the bottom has a bracket that might be a problem. If I do get them out, is all that's necessary is to change the main fuel jet, #10 in the diagram? Finally, do you think this is doable by a novice?

Yes it is doable, you are correct that it is item 10 in your manual. The challenge is getting the correct size screw driver to remove the jet. The jets are brass and quite brittle. You need to find a screwdriver that fits squarely in the slot and still goes through the passage way to reach the jet. I would go to your merc dealer and buy the jets first and then ask them to show you the screwdriver they use to remove jets. Often they will have modified a standard screwdriver to fit. You can see what they have done.

[DAaker]

Thanks guys! That was a great help. The whole thing took 45 minutes and that includes cutting off the screwdriver and modifying the blade to fit the jet slot.

I'll give you a report both for the motor and the fishing when I get back.

Onward!

[DAaker]

Hi guys, I'm back from lake Oahe. The fishing was fair to poor. I'll blame it on bad weather. The Merc ran strong with the .072 jets BUT, I had horrible gas consumption! Actually, I noticed the poor gas consumption here in CO before I left as well. The other guy I was with had a 115 Mariner and got at least twice the millage as me. The motor surges at 4,000 +/- cruse. I had the carbs rebuilt last fall and before that millage was much better. What to do?? Any ideas on a potential problem? I'll submit another post on this today as well.