Johnson Colt, which fuel/air mixture screw?

[wainy]

Hi All
I have recently purchased a 1.2 or 2hp Johnson Colt as a back up for my 5HP Seahorse. I enjoy tinkering with these engines but have a question, on the front of the engine there are two apertures (one is blanked off) and the other has an adjustment screw. My manual only details carbs with a high and low idle mixture screw. Does anybody know which screw this is (high or low) and how to adjust it. Many thanks

 

[racerone]

Re: Johnson Colt, which fuel/air mixture screw?

Model # is ?

 

[Vic.S]

Re: Johnson Colt, which fuel/air mixture screw?

Hi All
I have recently purchased a 1.2 or 2hp Johnson Colt as a back up for my 5HP Seahorse. I enjoy tinkering with these engines but have a question, on the front of the engine there are two apertures (one is blanked off) and the other has an adjustment screw. My manual only details carbs with a high and low idle mixture screw. Does anybody know which screw this is (high or low) and how to adjust it. Many thanks

When both fitted the upper one is the lowspeed adjustment anfd the lowe one the high speed.

I guess you only have the upper one, namely the low speedajustment

See Joe Reeves instructions for adjusting on the "Engine FAQs" board. Follow the link from the "Top secret file" if you wish

 

[wainy]

Re: Johnson Colt, which fuel/air mixture screw?

Model # is ?

Hi Racerone

Model JCOESE Serial Number B8450364

 

[wainy]

Re: Johnson Colt, which fuel/air mixture screw?

When both fitted the upper one is the lowspeed adjustment anfd the lowe one the high speed.

I guess you only have the upper one, namely the low speedajustment

See Joe Reeves instructions for adjusting on the "Engine FAQs" board. Follow the link from the "Top secret file" if you wish

Hi Captain
thanks for your response, the top needle aperture is blanked off with the bottom one (into the fuel bowl) accessible. Is this the high speed mixture adjusting screw?

 

[racerone]

Re: Johnson Colt, which fuel/air mixture screw?

The high speed is the bottom one.--------You may need to pop out a plug to get to the top one that is the slow speed mixture adjustment.------What is your motor doing / not doing ?

 

[Vic.S]

Re: Johnson Colt, which fuel/air mixture screw?

Hi Racerone

Model JCOESE Serial Number B8450364

A 1990 1.2 Hp model.

The parts diagrams show both adjustment needles!

Just noticed that you are in Wales It was probably made in Belgium?? ( Might be slightly different to models illustrated in the American parts lists)


I think Access to the slow running needle is blanked off as Racerone suggests. Prise the blank out of the cover and you should find it lurking in there.

good UK boating forums at YBW.com by the way, although iBoats usually the best for outboard advice

 

[wainy]

Re: Johnson Colt, which fuel/air mixture screw?

The high speed is the bottom one.--------You may need to pop out a plug to get to the top one that is the slow speed mixture adjustment.------What is your motor doing / not doing ?

Hi Racerone
The motor did not rev freely and I suspected the mixture was too rich. I also had my concerns the cooling system was not operating effectively. I removed the water pump and discovered the plastic spacer located beneath the pump appeared to have been damaged from heat and had partially melted, obstructing the water intake to the pump. I suspect the previous owner may have started it dry? I will replace the spacer and impeller. When I am satisfied the cooling system is OK, I will adjust the High Speed mixture, does turning the screw anti clockwise enrich the mixture? what do you suggest as an initial setting (no of turns out from screwed in). Thanks for your help.

 

[wainy]

Re: Johnson Colt, which fuel/air mixture screw?

Hi Vic.S
Thank you for your prompt reply and the information, do you recommend any dealers in the UK for spares?

 

[Vic.S]

Re: Johnson Colt, which fuel/air mixture screw?

Hi Vic.S
Thank you for your prompt reply and the information, do you recommend any dealers in the UK for spares?

Users of the YBW.com forums have had good service from Wills Marine in Kingsbridge Wills Marine Ltd | Zodiac Ribs, Nordkapp Boats, Evinrude Outboards, Engine Maintenance & Boat Storage

I have had good service from Oakley Marine, aka Outboards Direct, in Brighton :: OutBoards Direct ::

As I said earlier see Joe Reeves instructions for adjusting the carb needles
http://forums.iboats.com/engine-fre...sorted-carb-variations-joe-reeves-167352.html

 

[wainy]

Re: Johnson Colt, which fuel/air mixture screw?

Thanks Vic.S your help is very much appreciated.