Any omc single barrel carburetor mods for acceleration

**H2OPERF** · 09-07-2021, 08:05 AM

My 14ft jon boat with a 45ci 60hp rude falls on its face on accel... i'm thinking of welding up the carb bowls and moving the jet to the back of the carb. .. Has anyone done anything like this or other mods to help with this issue. Thinking also maybe open up the seats a little and or put another fuel pump on so each carb has its own? Overkill i know but its driving me crazy lol, I figure somebody on here has played with these carbs.

**powerabout** · 09-07-2021, 11:30 PM

Originally Posted by H2OPERF

My 14ft jon boat with a 45ci 60hp rude falls on its face on accel... i'm thinking of welding up the carb bowls and moving the jet to the back of the carb. .. Has anyone done anything like this or other mods to help with this issue. Thinking also maybe open up the seats a little and or put another fuel pump on so each carb has its own? Overkill i know but its driving me crazy lol, I figure somebody on here has played with these carbs.

60's did have some lean issues but rejetting fixed that.
Do you have a electric primer then you can add fuel on acceleration for troubleshoting.

**H2OPERF** · 09-08-2021, 05:35 AM

The boat launches really hard and noses up pretty high... its a pull start/tiller with no trim so i'm thinking when the fuel rushes to the back of the carbs the main jet passage is sucking air because as soon as the nose drops it takes off and will do it again until the boat gets moving and lays down. If i put weight in the bow it will take off better with only a light surge but then the bow sticks to the water and scrubs off too much speed. I just figured some one on here has had these issues with an SE or race boat with a 2 cyl. Power... the jetting is good on the top end so i don't think i can do much there, power trim would probably fix the problem but i want to keep the boat simple and light. I would like to put on some diaphragm mikunis on but that's another can of worms with the linkages though the adjustable jets would be nice.

**Instigator** · 09-08-2021, 06:13 AM

Bowl stuffers.

When I finally got my Vector dialed it did the same thing.

Would launch now up, clear the water and almost die, until landing.

Put bowl stuffers in the carbs and solved it.

Betcha a beer that solves it ��

**H2OPERF** · 09-08-2021, 06:35 AM

Thats exactly what it does...as the transom clears the water and skips foreward it just shuts off and then takes off and does it again. I did a search for stuffers before and couldnt find anything but I thought they were more for bouncing around in rough water.
I could probably just fill in the cavities with epoxy...

**H2OPERF** · 09-08-2021, 06:59 AM

Looking at the carb now and there is a lot of room for the fuel to go above the floats in the back. I will try filling it in, thx Gary.. think its my turn to buy next time ur down this way.

**powerabout** · 09-08-2021, 09:39 AM

I dont recall the factory ever making bowl stuffers for those carbs, they normally do it for cornering issues

**rhardwick** · 09-08-2021, 01:35 PM

This seems odd, I raced SST45's and we never had any issues like this even with tight turns that would definitely slosh the fuel in the carbs. I ran 56-58 main jets turning 7300 to 7500 RPM. SST45 powerhead is the same engine you have for the most part, has fixed timing and plastic reeds.
Are you running too much propeller bogging the engine down on acceleration? Those engines need to turn 6000+ RPM's.

**H2OPERF** · 09-08-2021, 03:38 PM

It has 57 mains, carson reeds, stock timing, 20p on 2.42 nitro... Runs great just accelerates really fast on the flat jon boat and looses fuel. Bunch of small boats around here on canals and i love spankin 90- 115hp 4 strokes with my little jon boat.

**H2OPERF** · 09-08-2021, 03:41 PM

The entire motor is built from parts but its basically a 60hp ph..

**powerabout** · 09-09-2021, 12:02 AM

Originally Posted by H2OPERF

The entire motor is built from parts but its basically a 60hp ph..

the 60 had a different piston design with a cut skirt, do that to later 45 and there is some power.

**Instigator** · 09-09-2021, 06:01 AM

Dave, I’ve had bowl gaskets cut to do the same thing and also filled the bowls w/epoxy.

**H2OPERF** · 09-09-2021, 06:23 AM

It runs perfect in every other way, 3 people in the boat it takes off smooth and pulls hard up to 6k. You would never know of any problem until its just me in the boat. I have been in the carbs several times while jetting and putting in Carsons reeds, which gave it a noticeable increase in mid range pull. I know the little gaskets around the emulsion tubes can give problems but they are new. Ordered some epoxy it can't hurt. Thinkin of goin to Jasper this yr.

**H2OPERF** · 09-09-2021, 08:58 AM

Power, I'm sure there is more there too but it was just supposed to be a jon boat motor, a 15in 50hp factory tiller with the low profile pull start only made a few years, a motor i allways liked. Problem is I can't leave a good runnin motor alone. Already picked up another block to mess with, why I don't know Lol.

**perfmarine1** · 09-11-2021, 08:51 PM

I would say you just need to richen up the the idle,you need a big load of fuel in there when you send in the air. Does it ever lean sneeze at idle,that Is a typical of a Reed swap