weird acting motor/probably carb

[andrew81]

ok, here it is. this year i installed boyesen reeds, wich i dont thonk is my problem but i thought i'd let you know "just in case".
i have to prime my motor every time i go to start it, hot or cold. if i pick my motor up it floods and is very hard to stART again. it seems to either want to idle and not want to go, or it will go and not idle. when its idleing i can rev it up and it seems to work fine. but as soon as i put it in gear and start to go it floods and shuts off. with great patience it will go and when it does it seems to work fine but as soon as i shut it off"same thing" i changed the needle valve, this didn't help. i also checked to make sure my main jet didn't vibrate loose. i've been thinking this was a "set up" problem but now i'm not so sure. my motor is a 20hp mercury, with a 25 carb, drilled exhaust, and i opened myreed dampers. but keep in mind that all these mods were done a couple of years ago, and the motor worked fine until this year. the motor is year 2000.
god i hope some one can help me out here, our boating season is very short on the miramichi river, soon the water will drop and it will be over for another year. kind of dissapointing when the season is only 2-3 weeks and youve got a ****ty working motor!!!

atk81

[alky6]

couple of things, when was the last time you changed spark plugs? Depending upon the type of float, sealed cork, metal or plastic, is the float filling up with fuel, is the boyancy correct? Check the needle and seat to make sure that there is not any dirt lodged in there. Also make sure that it does in fact seat. Do you have fresh fuel in it? Without any water in the fuel? That is where I would start.

Good Luck.
-paul

[andrew81]

thanx paul,
i've already changed the plugs, checked the "plastic"float and changed the needle valve. i even dumped the gas i was running and drained the carbs and added new gas ,,,this stuff didn't help... i'm stumped... i find myself spending more time scratching my head on the shore than actually boating...lol

[Karl 9W]

Fuel pump used on this motor? If so, maybe check out this department. Fuel pump acts as check valve in supply line while motor is off, fuel can siphon back to tank while motor is off if pump is faulty, besides causing running problems. I run a clear fuel line from pump to carb. NO BUBBLES ALLOWED!!!
Faulty or dirt contaminated pump can cause a tough intermittent problem. Any pump I've seen used (omc or merc) still has repair parts available from dealers. Also check all connections to be tight & sealed. You'll be surprised where the tiniest air leaks can occur (seen sqeeze bulbs develop tiny holes that don't leak fuel out but will leak air in!!). Karl.