2004 Mercruiser Bravo III stalls

Lucke

Recruit
Joined
Sep 3, 2008
Messages
3
We have a 2004 Mercruiser 4.3L Bravo III with Thunderbolt V ignition. A couple of weeks ago we thought there was a shift cable problem, seemed like it did not want to go into gear, only happened in forward. Had it checked out and they couldn't find a problem, it was an off and on thing. Did tighten a couple of screws and thought that might help. Last week, we hit a submerged log, badly dinged the upper prop, had it fixed, seemed to be fine.
(this is background). Anyway this week after we are out about 30 minutes, all of a sudden the engine tries to stall, rpms go to zero, happened over and over, did not seem to be as bad the faster we went, but would still hesitate.
Made it home, called the marina, they thought it might be the rotor and distributor cap, husband changed that out, had a greenish powder in the cap.
Ran it back and forth in our cove for probably 20minutes, ran fine. Tried going out the next morning, started all over again, except this time it did die on us. Started right back up, but kept stalling out. Took it over to the marina (not far) and it ran fine. Any ideas? Sorry this is so long.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: 2004 Mercruiser Bravo III stalls

When it dies, do you have spark?
 

Lucke

Recruit
Joined
Sep 3, 2008
Messages
3
Re: 2004 Mercruiser Bravo III stalls

Have no clue, sorry, I am pretty much just the passenger. It was running fine at about 20 mph when it first happened, all of a sudden the rpm's went to zero and then it kicked back in. Didn't seem to matter what speed we were at.
 

newport dave

Chief Petty Officer
Joined
Nov 21, 2004
Messages
458
Re: 2004 Mercruiser Bravo III stalls

A very common cause of this problem is Ignition Sensor failure. There is a very easy test procedure in the Merc service manual.

The other thing I would check (if it's an Alpha drive) is the shift interrupt switch, since it sounds like it has been acting up.
 
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