Engine Stalled when slowing down from 300 RPMS. Wouldn't Restart

MuskyHuntr · #1 08-01-2011, 08:38 AM

Was out on the lake cruising @ about 3400 rpms (25 mph) for about 20 minutes. went to Slow down & the engine stalls out???
Would not restart. Waited a 1/2 hour and still no restart..

Got towed back in to the ramp, drove home Checked a bunch of things... everything seemed OK... Hooked it up to the hose and the engine fired right up and ran fine..

A simialr thing happened earlier in the season.. slowed down from around 3000 rpm's to near idle when I seen sosmething in the water at the last minute and she stalled.. But she started right up and after navigating around the log we were on our way again.

So the question is what makes the engine die like that?
Can I fix it? If I can't then how do I get around it?

Engine is a 3.0 4-cyl Mercruiser 140 HP besides this the engine seems ot run very well.

Any help would be appreciated....Thanks

Destroyer · #2 08-01-2011, 09:25 AM

There's a thousand things that it could be, but it sounds like some kind of fuel related issue to me. Since you have spark, and air, then the only other thing it can be is a gas delivery issue..so it's either too little or too much gas being delivered to the engine. Did you pull a spark plug to see if it was wet? That would indicate a flooding condition. A dry plug would indicate a vapor lock/fuel starving condition. This is all just backyard mechanics thinking of course and I'm sure that others here can help you better than me... but that would be my first place to look guess.

MuskyHuntr · #3 08-01-2011, 09:41 AM

At the time we pulled plugs and found Cyl 1 & 2 to be dry... Cyl 3 was wet with gas...

Gas in carb too...

But in taking off plug wire 3 the wire came out of the boot and that was it.. Cal for the Tow boat with no way to fix the wire..

But after plugging in new plug wires it fired up fine..(4 hrs later)

And by then it had colled down, gas evaporated chike thermosta had cooled... basically conditios back to normal..

parishht · #4 08-01-2011, 11:05 AM

I know you are on a lake with fresh water, but mine was in salt water and the saltwater ate away at the gaskets. Check your compression inthe cyliders or if you know someone with a scope, have them look at your pistons.
My engine had slow water intrussion and eventually burned 1,3 and 6. I kept losing power over a three year period, started and seamed to run fine on land with hose, but put it in water and it would start and stall right out when put in gear, turned out to be running on three cylindars.
This could be worst case scenario for you.

spareparts · #5 08-01-2011, 06:34 PM

replace the points with a pertronix ignition, replace the coil while you're at it. You eliminate 90% of the ignition issues by replacing them