Mercury Bigfoot 25hp tiller - Idling ?

[CheezyPete]

Hi,
I've just acquired this Mercury Bigfoot 25hp tiller outboard with a secondhand boat I bought - its about 15 years old.

I've had it serviced including a carb service, and I've fuelled it with Apsen - the service centre said the engine was all good.

I've never used a petrol outboard before, so its all a bit new to me - it took a few attempts to start the motor, I had to put it in neutral and give it a bit of throttle for it to kick in.
It wouldn't idle, if I let the tiller throttle go it would cut out quickly . If I kept on the throttle and put it into forward, it got going but couldn't go slowly without cutting out - I had to keep the throttle up a bit all the time. It was OK all day but just this issue with not idling and stopping when going slowly.
Should this motor idle and be able to tickover without someone holding the throttle? Is this just an adjustment I need to make?

Hope I've not rambled on too long! any help much appreciated, thanks

 

[ThomW]

Have you tried adjusting the idle on the carb??

 

[oldman570]

You need to get a manual for that motor and read the carb section as how to set the idle and fuel mixture on it. There is a screw on the throttle linkage that sets the idle speed which should be done with the motor warmed up and running in water in FWD gear. Once it is set you can set the low speed mixture jet for the highest RPM and then reset the idle screw again. The motor dose need to have the throttle grip increased to the start position for the motor to start and will take a short time for the motor to get warmed up and run right. Also use a good 50 -1 gas oil mixture and preferably non-ethanol gas as the ethanol has bad effects on the rubber fuel lines an the rubber in the carb.