1994 Merc 150 NO POWER

[candcbrown]

I just pulled a tube behind my 94 procraft with a 94 150 Mercury for the first time today, and it had a very hard time getting past 10 to 12 mph. I finally did and ran ok after that. But then I stopped and it had the same problem again. I also had hard starting after the engine was warmed up-it started better cold than warm. Where should I start looking for problems?

 

[Mi duckdown]

Re: 1994 Merc 150 NO POWER

1. compression.

 

[CharlieB]

Re: 1994 Merc 150 NO POWER

Depends which carbs are on your motor.

A heavily loaded motor requires more idle fuel mixture for acceleration than a lighter loaded motor.

While everything may seem fine with your boat NORMALLY< the additional load of the tube increases the fuel required to accelerate.

If your carbs have idle mixture screws, back each one out CCW just the width of the screwdriver blade and retest acceleration.

If no idle mixture screws then the carbs need cleaning and reset the float levels very carefully, increasing fuel level 1/16 inch from the factory setting.

Warm starting proceedure depends how warm, how long the motor was off before resstarting. Most restart with just the turn of the key. Some need a little throttle.

Describe your problem and your restart proceedure.

 

[candcbrown]

Re: 1994 Merc 150 NO POWER

Depends which carbs are on your motor.

A heavily loaded motor requires more idle fuel mixture for acceleration than a lighter loaded motor.

While everything may seem fine with your boat NORMALLY< the additional load of the tube increases the fuel required to accelerate.

If your carbs have idle mixture screws, back each one out CCW just the width of the screwdriver blade and retest acceleration.

If no idle mixture screws then the carbs need cleaning and reset the float levels very carefully, increasing fuel level 1/16 inch from the factory setting.

Warm starting proceedure depends how warm, how long the motor was off before resstarting. Most restart with just the turn of the key. Some need a little throttle.

Describe your problem and your restart proceedure.

Thanks, in general, I have problems with idling-the motor dies many times after I run it wide open, and then pull it back to an idle. Then it is hard to start, or it starts and dies several times. I have not been giving it any throttle thinking that it would flood it when hot, but maybe that is a problem?

This motor has three carbs, so am I looking at 6 idle screws to adjust, correct? I think I see them, but am not 100% sure.

 

[CharlieB]

Re: 1994 Merc 150 NO POWER

IF the carbs have idle mixture screws there will be one on each side, the two barrel carbs are lilke two carbs sharing a common housing.

Dieing at idle may also be caused by air sucking into the fuel system between the tank and fuel pump, fails to keep all carbs full at idle yet flows more fuel at higher rpm. Simple test, replace a section of hose immediately after the fuel pump, run the motor and watch for any bubbles passing thru the line. Only use the clear hose for testing, remove it and reinstall marine rated hose when finished.