1981 50 HP Mercury bogs when warmed up

[breeder44]

I have a 1981 Mercury 50 HP motor with the thunderbolt transmission. The boat starts good and runs good when you first take off but as soon as you stop and then try to go again it just keeps bogging out. Then when you let it cool down for a while it runs good but when you stop and it's warm again it wants to bog out when I shift into drive. I put new plugs in it and cleaned the carbs so far. Any suggestions or ideas of what could be causing this?

 

[captain_cooke]

Re: 1981 50 HP Mercury bogs when warmed up

I'm no expert but from other posts I've read on here, I think it may be a coil pack problem...seems to be the usual answer to engines that bog down when warm...

 

[breeder44]

Re: 1981 50 HP Mercury bogs when warmed up

If that's the problem, would it be a costly repair? I'm brand new to boating and really don't know much about marine motors.

 

[breeder44]

Re: 1981 50 HP Mercury bogs when warmed up

ttt

 

[bgbass.1]

Re: 1981 50 HP Mercury bogs when warmed up

it could also be getting hot that would make it bog when hot

 

[breeder44]

Re: 1981 50 HP Mercury bogs when warmed up

It's got lots of water coming out so it should be cooling the motor.

 

[imported_skraps]

Re: 1981 50 HP Mercury bogs when warmed up

Sounds as if you have a starving problem. Rebuild the fuel pump its easy and cheap to do.

 

[hkeiner]

Re: 1981 50 HP Mercury bogs when warmed up

There are lots of possibilities. Replacing parts at random or on a hunch (educated guess) without success can be frustrating and more expensive than necessary. Some things you can do to narrow down the problem are:

1) Temporarily connect a portable tank directly to the motor to see if the problem goes away.​

2) Check for fuel starvation during the bog by following the Mercury Service Advisory at the following link. http://www.marinepartsman.com/Mercur...2001/EN_17.PDF​

3) Check for adequate spark during bog by using a SmartTach meter or timing light connected to the spark plug wires one at a time.​

4) Check for adequate primary voltage during bog by using a DVA meter.​

If none of the above tests provides any clue to what is failing, there are many other troubleshooting steps possible. Do a search on this forum, check this forums FAQ section, or search the web. Below are some useful links too.​

Good luck​

http://www.homestead.com/dolphinmarineservice/Ign5.html​

http://outboardparts.com/troubleshoo...eshooting7.htm​