all or nothing

[chipben]

hi, i have a 1975 4.5hp mercury outboard.
it had not been used in about 15 years, once i had cleaned and replaced the carb i connected the fuel line and she started. It ran for a good 3 hours or so then spluttered a fair bit and eventually died. It turned out that it wasn't the best idea to use fuel which was 15 years old! So i cleaned the carb again and replaced the fuel pump. I hooked it up again (fresh unleaded fuel/oil) and it will only start with wide open throttle and once it has started it will not tick over it will only rev up high or nothing at all. I tried adjusting the mixture screw but it didnt help.
Is there an idle screw on the carb?
Any ideas as to solving this problem?
thanks in advance Ben

 

[Silvertip]

Re: all or nothing

If you used 15 year old fuel its funny it started at all. The fact that it at least runs at higher speeds indicates the carb is again fouled with gunk from the old fuel. You really need to clean the tank, flush the line and open up and clean the carb again.

 

[chipben]

Re: all or nothing

ok silvertip ill do what you recomended. i did clean the tank but not the fuel line.
Do you think that the engine will have a bit more power with fresh fuel?
50:1 i presume is the corect fuel/oil ratio?

 

[Laddies]

Re: all or nothing

The idle pickup tube is plugged, in some cases you can't get them out to clean them properly but without removing it you can get them clean by using spray carb cleaner and air pressure to blow it out

 

[chipben]

Re: all or nothing

The idle pickup tube is plugged, in some cases you can't get them out to clean them properly but without removing it you can get them clean by using spray carb cleaner and air pressure to blow it out

laddies im not too sure which tube is the idle pickup? Is it the one that sits at an angle just in the throat of the carb?
I thought i had blown air through all tubes and holes in the carb perhaps i missed that one. it must be something simple (i hope)

 

[Laddies]

Re: all or nothing

No thats not it, the idle pickup tube runs from the area behind the high speed jet to the side of the low speed adjust screw it's either under a brass plug on the top of the carb or is part of the plug. If you don't have a manual go to the parts manual at the BAM Marine site and ck it out

 

[chipben]

Re: all or nothing

ok thanks laddies ill ck it out

 

[Laddies]

Re: all or nothing

hope this works