Whats wrong with this motor

[twebb]

1986 mercury 90hp inline 6. Just rebuilt the carbs,set idle mixture screws at 1 1/2 out. Ran the boat on the muffs at home and it idle good. Put it in the water and she ran great, great hole shot, it even ran 4 mph faster than before (used gps). Ran it for about 45 mints, so i was happy. Got back to the dock and it stalled in neutral, than would not start, had to raise warm-up lever to get it to start. Back at home on the muffs, got it to start in neutral but wanted to stall so every time i hit the choke it came to life for a few seconds than tryed to stall again. Keep in mine never did a link and synk, but it still ran great for 45 minits. What do i check for now. Thanks for any and all help guy

 

[shipoffools]

Re: Whats wrong with this motor

I would check the fuel pump. Rebuild is cheap and easy and might solve your problem.

 

[wrench 3]

Re: Whats wrong with this motor

May have picked up junk in the carb. Did you replace the fuel filter? Is there water in the tank? Is the fuel filter plugged up?

 

[twebb]

Re: Whats wrong with this motor

i replaced the water/fuel filter 2 months ago, rebuilt the fuel pump and replaced the inline fuel filter 14 months ago. I put all new fuel lines in the motor plus from tank to motor when i did the carb rebuild. The primer bulb will not get hard the rest of the day after the motor has run. Only the next day after the motor is cold will it get hard again, is this normal? I will rebuild the fuel pump again this weekend to see if that helps. Thanks for the help guys.

 

[Chris1956]

Re: Whats wrong with this motor

Maybe you have bad carb floats? Just a guess....

 

[carholme]

Re: Whats wrong with this motor

Before you tear anything apart, verify the fuel pump. If you can get it to start, have someone standing by on the primer bulb and as soon as the engine falters, start pumping the bulb and keep pumping it. If the engine stays running, keep pumping and advance the throttle slightly to see if the rpms increase. If this is satisfactory, you can suspect the fuel pump as you have become the fuel pump by your pumping action.

Gerry

 

[twebb]

Re: Whats wrong with this motor

went out this morning, primed the bulb (it got hard) motor fired up and idle fine. seems like the problems always start after the motor gets hot. what should I check now? thanks

 

[MH Hawker]

Re: Whats wrong with this motor

Sounds more like you need to adjust the carbs on the water.

 

[twebb]

Re: Whats wrong with this motor

Thanks Hawker, but what should i do for more adjustment if it is running good at that time? Again, thanks for any advice.
Tom

 

[wrench 3]

Re: Whats wrong with this motor

When it starts acting up, do you still have good spark? The symptoms for weak spark and lean fuel mixture are almost identical.