Mercruiser 30L dies

"Have never had any problems w

"Have never had any problems with this engine till this year (ethanol maybe?). It is a 1990, with an M2 carb. Starts fine, and runs O.K. at higher rpm (no load), but when I bring it back toward idle, she cuts out and dies, then I cannot get it started again till the next day. I've "pumped" the fuel, and it looks O.K. Cleaned the in-line filter, but am at a loss as to what to do next. I tried to find a float bowl drain, but couldn't see one? I've added dry gas and stabilizer, thinking the gas may have soured over the winter, and added 15 fresh gallons; still no joy. Any suggestions?"

"adding dry gas wont help, cou

"adding dry gas wont help, could be soured over the winter. What color is it? Light Yellow(bad) or Goldern Yellow (good) did you notice any bubbles at the bottom of the container? (water)

Do you have a fuel/water Separator ? (looks like an oil filter but says Fuel on it)

Else could be the carb is a bit gummed up, not store well over the winter, I think the Stabil is having problems with the Ethanol. (own opinion-unconfirmed)

Might need to have the carb torn down and cleaned and rebuilt."

"Thanks for the ideas Brian, G

"Thanks for the ideas Brian, Gas looked golden yellow, but smelt a bit odd. I do not have a water separator. I was hoping for an "easy" fix, as opposed to re-building the carb; my last resort. After reading some other threads, I'll check the tank vent, and replace the condenser. The odd thing is that when it stalls and I try to re-start it, it won't fire even when I spray ether into the carb - wierd? The carb has a single idle screw. If these easy fixes don't work, I'll back it out and try spraying carb cleaner in the hole. Does this float bowl have a drain screw (Mercarb M2)? I know I'm grasping, but am open to other suggestions."

"could it be the interuptor sw

"could it be the interuptor switch is bieng activated?

Look at the bracket where the shift cables are mounted on the engine and make sure the little roller on the microswitch is in the MIDDLE of the V notch.

Also is this a point ignintion?

If so, when running a point ignition the points and rotor and condenser should be replaced EVERY YEAR.

I would have 2-3 1 gallon ziplock bags full of points rotors and condensers every spring time after doing a spring tune up on a customers boats. EVERY YEAR!!"

""M2 carb. Starts fine, an

""M2 carb. Starts fine, and runs O.K. at higher rpm (no load), but when I bring it back toward idle, she cuts out and dies, then I cannot get it started again till the next day."

I assume you are testing the engine on ear muffs and a hose. Limit your "no load RPMs to 2000. Like Brian said, I think you need to remove the carb and give it a good soaking to clean the crud out of the idle circuits. Make sure that you get the correct carb base gasket--VERY important to get the proper atomization of fuel at idle. Get it from a dealer. It is thicker than the one in aftermarket kits. Use the carb specs in a manual and not the kit.

"Does this float bowl have a drain screw" No.

Have you pulled the flame arrester off when it won't start and checked the choke plate to see if it is open or does it close? If it closes when the engine is hot then it needs attention.

"Gas looked golden yellow, but smelt a bit odd."

Did it have an odor of varnish? Yes; bad gas? Add one can of SeaFoam for each 10 gallons of gas. Adding Stabil to old gas does very little; it should be added to an empty tank before refill. Stabil makes a blend just for ethanol dispersal.

Add a fuel/water separator filter between the fuel tank and fuel pump."

"Pete, [b]it won't fire ev

"Pete, it won't fire even when I spray ether into the carb - wierd? The carb has a single idle screw.

you didn't mention in the first post about not starting when you sprayed into the carb, if that's the cause it could be ignition !! Or the Shift interupt switch as Kghost."

"Got back up to camp, and gave

"Got back up to camp, and gave the thing a complete tune-up. New cap, plugs, wires, points and condenser. Thing runs fine now, however, I set the timing at 6 degrees BTDC (book) but it ran smoother at 15-20 BTDC. Strange. Although I have the right firing order, the book I have shows a diagram with the wires "off" one post on the cap counter-clockwise. However, when looking throughout the book at actual engine photos, my wires are connected the same. Hummm, any thoughts?"