Mercruiser 3.0L spark plug gap

[stangrrr]

Hello all,

I have just purchased a 2000 suntracker regency 25 pontoon.

I have a Mercruiser 3.0L (S/N OL631822), I changed the plugs, wires, dist, and rotor. The manual, and everything I have read so far states my gap should be .035, but the flame arrestor states it should be .045 (cant be sure it is the original flame arrestor becasue the engine serial number is blank on the flame arrestor.

I set the gap to .045 but the engine is difficult to start, and has a rough idle until it is warmed up.

The old plugs seemed to be at .040.

Does anyone know what the gap should be for this engine?

Also, I have an electric choke, but the idle cam seems to lock the choke in full open. I loosen the idle screw, which frees up the choke cam, and then the choke moves freely as it should, and is in the almost closed position when cold. The electric part of the choke works fine, but when I move the throttle forward, the cam locks the choke wide open again and it is stuck there even when the engine cools back down. I have to loosen up the idle screw to free up the choke again, but as soon as I move the throttle forward, it locks it in wide open again.

Any help would be great!
Thanks!

 

[Bondo]

Re: Mercruiser 3.0L spark plug gap

Hello all,

I have just purchased a 2000 suntracker regency 25 pontoon.

I have a Mercruiser 3.0L (S/N OL631822), I changed the plugs, wires, dist, and rotor. The manual, and everything I have read so far states my gap should be .035, but the flame arrestor states it should be .045 (cant be sure it is the original flame arrestor becasue the engine serial number is blank on the flame arrestor.

I set the gap to .045 but the engine is difficult to start, and has a rough idle until it is warmed up.

The old plugs seemed to be at .040.

Does anyone know what the gap should be for this engine?

Also, I have an electric choke, but the idle cam seems to lock the choke in full open. I loosen the idle screw, which frees up the choke cam, and then the choke moves freely as it should, and is in the almost closed position when cold. The electric part of the choke works fine, but when I move the throttle forward, the cam locks the choke wide open again and it is stuck there even when the engine cools back down. I have to loosen up the idle screw to free up the choke again, but as soon as I move the throttle forward, it locks it in wide open again.

Any help would be great!
Thanks!

Ayuh,... Welcome Aboard,.... The choke should close, Only when the motor is cold, 'n you advance the throttle to Wot, to set it....

 

[ktbarrentine]

Re: Mercruiser 3.0L spark plug gap

Here is a decent thread on adjusting the choke.... (I was looking for a sticky thread on this but couldnt find it...do we have one?)

http://forums.iboats.com/showthread.php?t=487694&highlight=electric+choke+works

HTH! KTB

 

[stangrrr]

Re: Mercruiser 3.0L spark plug gap

Ok, I understand the choke now Thanks, that was a big help. It is working correctly.

I will try starting it up this evening and give an update.

Can anyone verify the what the spark plug gap is?

 

[Don S]

Re: Mercruiser 3.0L spark plug gap

According to the service manual, it should be .035. States that in several places in the manual.
The Maintenance Procedures manual for your engine also states .035

 

[stangrrr]

Re: Mercruiser 3.0L spark plug gap

Update:

The engine started much easier with the choke working properly, thanks all! But still had a rough idle. I started to change the gap back to .035, got two done then the rain started. Will finish this evening and post update.

 

[stangrrr]

Re: Mercruiser 3.0L spark plug gap

Finished changing to .035, seemed much harder to start, idle seemed much rougher, seemed ok after warming up, but stillpopped a lot as it did with the gap at..045. Not sure what to try next except maybe timing?

 

[ktbarrentine]

Re: Mercruiser 3.0L spark plug gap

I would agree that a timing check is warranted, plus the other normal electrical checks that go along with that. Recheck your choke adjustment too, just to be sure. Are you convinced it is not carb related? When is the last time the carb was rebuilt?

 

[stangrrr]

Re: Mercruiser 3.0L spark plug gap

Probably never, I don't know the history of this boat, and it doesn't look like regular maint was kept up. I've adjusted the mixture screw per the manual, it does effect the engine so at least I know it is working, but I was wondering if I rebuilt the carb if that would help. Do you know how long they usually last before requiring a rebuild?

 

[Bondo]

Re: Mercruiser 3.0L spark plug gap

Probably never, I don't know the history of this boat, and it doesn't look like regular maint was kept up. I've adjusted the mixture screw per the manual, it does effect the engine so at least I know it is working, but I was wondering if I rebuilt the carb if that would help. Do you know how long they usually last before requiring a rebuild?

Ayuh,.... Til the very 1st time more Crap is introduced from dirty fuel....

 

[stangrrr]

Re: Mercruiser 3.0L spark plug gap

I will get a carb rebuild kit on Monday and give that a shot, will try to have done prior to next weekend and let you know how it turns out.

 

[stangrrr]

Re: Mercruiser 3.0L spark plug gap

Got the carb completely disassembled, carb fuel filter was a third of the way full of gunk, probably the only thing I had to replace but I decided to go thru with a full rebuild. My question is about the water separator, I don't have the kind that looks like an oil filter, I have the filter bowl bail type, it is very difficult to get to, do you think this should be changed as well? Or do you think I can get away with putting a treatment in the fuel to remove the water if any (not sure if water is trapped in seperator)

Thanks

 

[ktbarrentine]

Re: Mercruiser 3.0L spark plug gap

My question is about the water separator, I don't have the kind that looks like an oil filter, I have the filter bowl bail type, it is very difficult to get to, do you think this should be changed as well? Thanks

Are you referring to the filter on your fuel pump? If so, that is a filter, not a separator. You can (should) replace that, too. You may not have a water separator. Can you provide a photo?

 

[stangrrr]

Re: Mercruiser 3.0L spark plug gap

I will try and get a photo. I rebuilt the carb, replaced the base gasket with the one in the kit (same thickness), doubled checked everything (i think), put pump lever on lower notch, fuel kept flowing into carb, moved pump rod to middle hole, seemed to stop, can't get boat to start, any thoughts (might still be flooded but I let it sit for two hours, still won't start).

 

[stangrrr]

Re: Mercruiser 3.0L spark plug gap

The gas dripping seemed to be caused by the idle screw adjusted in to far, if I back it out, the fuel quits dripping from the venturi, but then it just turns over but no start, when the fuel was dripping it seemed like it tried to start, until eventually flooding (i think).

 

[stangrrr]

Re: Mercruiser 3.0L spark plug gap

Took the carb back apart, found I didn't measure the float drop correctly, put carb back in and boat runs great, thanks for the help!

 

[313gold]

Re: Mercruiser 3.0L spark plug gap

Update:

The engine started much easier with the choke working properly, thanks all! But still had a rough idle. I started to change the gap back to .035, got two done then the rain started. Will finish this evening and post update.

Did you ever finish? I hope so lol been years