BoatBanter.com - View Single Post - 1989 mercruiser 3.0 stalling after 30 min

Hank©[_2_]

On 5/21/2013 11:37 PM, wrote:
On Tue, 21 May 2013 21:36:14 -0400, Hank©
wrote:

On 5/21/2013 8:41 PM, Wayne B wrote:
On Tue, 21 May 2013 02:55:41 -0400, "Eisboch" wrote:

"Rupp0003" wrote in message ...

1989 merc 3.0 starts fine, runs fine for about half an hour at any
speed
or rpm then starts to miss and will eventually stall. Fuel dripping
from
flame arrestor but only once rough running starts. Will sometimes
restart after a few minutes and run ok other times will continue to
run
rough and stall.

Are there any members out there that might have some insight into what
the problem might be?

--------------------------------------------------------------------

Bad coil. (Goes bad when warm .... ok when cold.)

====

Probably right. I had that problem on one of my old 454s. To make
it worse, some genius decided that the coil should be mounted very
near the exhaust manifold.

The dripping fuel makes me think needle and seat or heavy float.

I had that problem on an old Corvette (bad float) and it was fine if
you didn't slow down.

The tie breaker is to just check the spark when it is not starting.
One of those enclosed gap testers is safer on a boat than the old
screwdriver method. That is particularly true if you have gas leaking
around/

Here's another one. Starts up and runs fine for a few minutes after
putting a load on. Moisture on or under the metal baseplate vaporizes
and causes crossfiring at the distributor cap.