mercury starting problems

[tomko]

I have a 1983 40hp mercury engine that is hard to start. If I take the spark plugs out it cranks fine, but with the plugs in it seems to lock up. Sometimes it starts but it won't idle. Thanks.

[mellowyellow]

welcome tomco I'm not an expert, but hate to see someone's first post go unanswered. 3 things needed arefuel, air & spark. which one you are havingproblems with is a guess with the info provided.start by doing a search (see above RED button).2nd get yourself a manual. if u don't want to buyone, go to the library. start with the simple cheapfixes... clean carbs, good fuel, good oil etc.there are real experts on this site who are happyto help you for free, but you gotta give themsomething to work with.good luck M.Y.

[tomko]

The boat was sitting for over a year and when I tried to start it it ran, but then stalled. When I got it restarted again with fresh gas, it wouldn't idle. Now it doesn't hardly roll over. It seems like it is locked with compression because when I pull the spark plugs it rolls fine. It seems to have good spark. thanks.

[dmessy]

Sounds like a weak start battery or loose/corroded connections, check both. Rough idle after storage is prob. fuel related. Start anew with fresh fuel mix, drain and clean float bowl(s) and main/idle jets. Prob. gummed up with varnish. Was the motor properly stored?(ie;fuel stabilizer added, ran, fogged,cylinders oiled,turned over occassinally?)Good luck...

[tomko]

I cleaned the carb and blew it out with air. Everthing seems open. I changed the spark plugs. I changed the gas again. The motor starts and runs if I use the throttle increase button on the control, but it still won't idle. I tried to adjust the idle screws, but it didn't work either.It just won't idle when my control is in neutral. thanks.

[RICKRICK1]

tomko, did you change any settings inside the carbs, did you changeout (replace)the needles and seats , had a similar problem, found out i needed new needles and seats since then ok. also did you soak your carbs in a good carb cleaner, may have varnish in places you could not get to that has worked loose and is now blocking something. Did you link and sync carbs after reinstalling them.You didnt say but do you have a manual, as this will help more than anything.