1980 Mecury 40hp - Engine Lacking Power

[jayard78]

I have a project motor that I have done SOOOOO much too and now it seems to need some fine tuning.

When I'm out on the water is seems like it is surging (lacking power) when I have the throttle all the way forward. It barely runs when the flap on the front of the carb (labeled 37 in pic) is closed and in order to get if running kinda well you need to have some one slowly open the flap all the way while someone else pushes the throttle forward.

It is inconsistent too, Friday nite the water was calm and it got up on a plain and just cruised. The very next nite the water was a little ruff and it seemed like the engine could not get up on a plain and was lacking in power. You could hear the motor when it was full throttle sounding like it wanted to go but could not.

So here is what I have done to this thing:

New plugs and wires
water pump and housing
New switch box
rebuilt carb but had issues: when I rebuilt the carb the needle seemed like it was sticking a little but if you tapped the bowl lid it would free up.
New throttle and cables

I think the key to my problem is in the carb. Help a guy out please.

 

[Laddies]

Re: 1980 Mecury 40hp - Engine Lacking Power

You still have a fuel problem, did you replace the inlet needles, clean the idle tubes and set the float level and check the fuel pump, your problem could be anyone of these things.

 

[mark_gober]

Re: 1980 Mecury 40hp - Engine Lacking Power

I'm not familiar with your particular motor, but I'd take a can of chemtool or carb cleaner out there with me and when it's running poorly, shoot a small shot of it into the carb. If you aren't getting enough fuel, that should rev your engine. You may have to tweak your shot length, but it would probably be really quick. If that doesn't work, have you thought about your switch box?

Mark