1992 55 HP Rough Idling In Forward Gear

My engine runs rough when I put it in forward gear. It will run fine if I increase the throttle. If I put it in reverse it idles fine no roughness but as soon as I put it in forward gear it runs rough and might quit. That presents a problems when driving it onto my trailer. The model number is: C55ELRQ. It has two new carbs and a new fuel pump and new plugs. Coils have not been replaced. When It is in neutral it runs fine. What can it be? Help if you can. Thank you and have a great day.

A compression test is the most important trouble shooting step to do.----Report your numbers.----------Very little goes wrong with carburetors that warrants installing new ones !!

Well I finally got myself a Actron compression tester and tested the engine. I got a solid reading of 140 psi on both cylinders. Here I will reiterate some of the problems of rough running. As I increase the throttle it continues to shutter or shake and when I reach a particular point the vibration,shaking and shuttering goes away and she runs like a scalded ape smooth as can be. There is something about the reverse gear. When I put it in reverse, I have to be very careful not to go too far down with the throttle handle or it will grind the gears instead of applying power. I can deal with all these things mentioned but would like to know if there is something I can do to eliminate them. If you need to ask me a particular question I will do my best to answer it. Thank you for you patience.

I only have two adjustable screws, one is for the idle and I don't know what the other one does. It sets on top of the carb near the rear. I have not made any adjustments at all. It was this way when I bought it. I just know that the carbs are new and the fuel pump is new and I put new plugs in myself, and as i said before it runs flawlessly once I pass the roughness. As far as hesitation there is none. I am going to check my manual and see if they identify the adjusting screw on top and if it's the slow pilot I will try adjusting it in the water. Thank you for your reply.

Both carbs seem to open at the same time as they are ganged together and there is no play or slop in the mechanism.

I just checked my Service Manual and it calls it Pilot Screw and that's all it says about it.