9.8 Mercury Cold Start Problem

[Blake0912]

I have a 1975 mec 110, The motor idles great and will go full power no problem, but I can not get it to start without sprating a little pre mix gas into the carb then it will fire with half a pull. I have rebuilt the carb/fuel pump it has a new fuel tank and line. What could be causing this problem? Thanks for your help

 

[Maxz695]

Re: 9.8 Mercury Cold Start Problem

float level too high or too low. Adjust for best holeshot and the problem may be fixed you could be running too rich or too lean. this will affect starting significantly. also check your charging system if the rectifier is not working properly it will also affect idol running and low speed running conditions as well as if overcharging blow up your switchbox at hi RPMs what is you tach reading at WOT?

 

[oldman570]

Re: 9.8 Mercury Cold Start Problem

If you have not checked the timming and done a link & sync on the motor yet could be the trouble. If the motor was starting easy before the carb work was done the float setting could be the trouble along with the low speed jet setting. If you did not replace the fuel lines from the tank conection to the carb, there is a good chance that thier inner jacket is deterated and a small pice could have broke loose and pluged the idle jet passage. JMO
Oldman570

 

[Laddies]

Re: 9.8 Mercury Cold Start Problem

Two most common problems with that carb is the spring on the choke butterfly will get weak or break allowing half of the butterfly to open when cranking the engine or the choke cable is not adjusted right and the choke will not be closed completely when the detent is suppost to be holding it closed.

 

[Blake0912]

Re: 9.8 Mercury Cold Start Problem

I have not done a link & sync on it, if I just do a small sqirt of pre mix into the carb it will fire on the first pull and idle low/speed up and go wide open. I do not have a tach on this motor. How should this float be set? I agree with it may be something to do with my choke, Ill try to adjust the cable, but it looks like the butterfly is closing all the way when the choke is pulled out.

 

[quicktach]

Re: 9.8 Mercury Cold Start Problem

Sounds initially like gas starving. Check all the adjustments as per shop manual for the motor. Check float level for parallel to body of carb. Before carb rebuild - did you really clean out all the passages in the carb - solvent plus compressed air ? Check for fuel tank vent clear. Are you choking prior to cranking over ? Gas filters clean ? Carb gasket in Ok ? All carb/manifold bolts tight ?

 

[Maxz695]

Re: 9.8 Mercury Cold Start Problem

I agree check carb fuel starvation. float level needles and seats. If the engine seems fine when spraying fuel into the carb then the problem lies in the delivery. Lines filter hoses etc.