1983 25hp mercury Help!

[FireNHunt]

i have a 1983 25hp mercury serial 5971170. i had it running the other day and my buddy and i was messing with the air mix screw since it was running rough. we turned it off and now it wont start. it backpops out the exhaust when you pull it. i have the fuel mix at 50:1. is there a starting point at which you set the set-screw at? anything else it might be? any help would be greatly appretiated.

thanks in advance
Zachary

 

[PeteB_2000]

Re: 1983 25hp mercury Help!

i have the same engine and from it gripping the thread mine is set to 5 full turns

 

[FireNHunt]

Re: 1983 25hp mercury Help!

thanks, however my motor will still not start back up. i check spark with a 1/2" gap to block via screw driver and it has good spark in both cylinders. anyone have any ideas? :%

 

[FireNHunt]

Re: 1983 25hp mercury Help!

my buddy things the timing is off. could possible be it. and if so how can i adjust this?

 

[FireNHunt]

Re: 1983 25hp mercury Help!

anyone have some ideas?

 

[deejaycee_2000]

Re: 1983 25hp mercury Help!

the carb air screw must be turned in-wards to SOFT STOP, then turned out-wards 1 and a half turns, then when the engine is warm adjust it slightly until it sounds good, but sounds like you need to rebuild those carbs ....

 

[ozziebob]

Re: 1983 25hp mercury Help!

deejaycee is on track 1 1/2 turns out then place in gear and adjust inwards till motor slows then back out till motor runs ruff then set a midway. If suspect timming connect timming light and pull engine over and get the reading post us a reply with your results but i think it is unlikely it is out.