1991 25hp Merc o/b Cold Start

[baironhorse]

I got a 1991 25hp Merc. Lately it has been giving me a hard time starting cold. First time I ran it this season it started on second crank. Last couple of outings it has been a pain to start cold and needs a dozen or so trys.....when it is warmed up it starts first shot..It is not a tiller motor and I have choke out and fast idle lever up when starting....Any suggestions? Maybe give me a complete run down of choke positions etc...anyone experience this?

[mike rousseau]

When was the last time it had a make over???

 

Spark plugs

Fuel filter

Oil change

Run cleaner threw the engine

 

...

Edited July 18, 2011 by Musky Mike

[baironhorse]

Its been about 2yrs....was all checked before winter and all good then? Doea running mix on the richer side make a diffence?

 

When was the last time it had a make over???

 

Spark plugs

Fuel filter

Oil change

Run cleaner threw the engine

 

...

[Roe Bag]

I'd take a close look at the choke. The linkage may have slipped and the choke is no longer fully engaging. Had this happen with an earlier outboard and a lawnmower as well. If that's not the case then throw a new set of plugs at it and an accurately mixed fresh batch of fuel.

I'm a firm believer in Sea Foam as well. Pour in about 200 ml. into a 25 litre fuel tank. Add the proper amount of oil. (assuming it's a two stroke) Then fill it with gas so it is all thoroughly mixed.

 

Good luck.

[Old Man]

Sounds like it needs a good carb cleaning. The pilot circuit it the carb may be plugged.

Edited July 18, 2011 by Old Man

[NAW]

I'd take a close look at the choke. The linkage may have slipped and the choke is no longer fully engaging.

Good luck.

 

This happened to my 89 15hp merc. The arm on the carb that pulls out when you pull the choke was not pulling out all the way. To find out if that's your problem, take the cap off, and pull the choke, see how far out the arm comes.

 

When it's cold, with the cap off, pull the arm out your self, and try starting it that way. Mine fires on the first pull every time that way..

[baironhorse]

not to sound stupid..but what would be the correct starting position for the choke...i.e. should it be turned all the counter clock wise at starting and once started turn clock wise to adjust idle...or is this not necessary with the fast idle lever?

[Roe Bag]

not to sound stupid..but what would be the correct starting position for the choke...i.e. should it be turned all the counter clock wise at starting and once started turn clock wise to adjust idle...or is this not necessary with the fast idle lever?

Personally I'm only familiar with manual chokes on smaller outboards/lawnmowers/chainsaws etc.. You simply pull or push a knob and the choke is activated. Generally when a choke is activated it is fully closed meaning that you are unable to see down the throat of the carburetor. In some cases, the choke does not completely close. A small space remains at the top and bottom to allow air into the engine. In other cases, the choke does fully close but has a small hole in the butterfly allowing air to enter.

Given the fact that once warm, the engine operates fine, then it has to be the choke. If it's cable activated it's probably just a case of the cable having slipped out of adjustment.

 

Good luck.

[baironhorse]

Thanks I will look into choke!