1980 merc 70 horse,help.

[captaincanuck]

hello guys,I have a 1980 merc 70 horse 3 cylinder.
my problem i have is i had it tuned up and got it to start no problems with muffs on.
I put it into gear and idles nice both forward and reverse.
the problem is i went to put it in the water and give it a small run around the lake ,it fired up no problem .
after i had it at idle for a minute i put it in reverse and started to back out from the dock just at idle.
when i put it in forward gear it did the same thing no problem.
then i went to give it some gas and it sped up a little then it would not take anymore it just kept dying?????
forward or backward it did the same thing.
so i pushed the button on the shifter to allow you to use the shifter for gas with out it being in gear and it reved up fine no problems at all.
but once again trying to get it to take some gas after it idles it just keeps quiting.
please any help you could give.
regards ,gord.

 

[yamatech43]

Re: 1980 merc 70 horse,help.

This is easy.....it takes only drops of gas to rev an engine in neutral with no load on it....takes a nice stream of gas to rev up engine with 1000 pound
load on it...see? Your carbs are stopped up...running the engine like this will destroy it since lean gas equals lean oil...see? Have to remove carbs, take apart carbs and soak carbs in cleaner....NOT SPRAY. Who worked on your boat? They didn't put it in water or test tank?

 

[captaincanuck]

Re: 1980 merc 70 horse,help.

ok i see, he did nothing with the carbs only adjusted spark and changed a coil.
the guy i got the boat from said he fooled around with the idle jets or screws on the carbs and that they may be out of adjustment.