4.3 Will not run!! Help!

[mrnmrskyle]

Well, I have had my 1989 2bbl carbed 4.3L mercruiser out a bunch this summer, always ran perfect. Today on the other hand! We were cruising, and it started to sputter, almost sounded like it was spark knocking as well. it ran for about 1/4 mile surging and then died. I got it to run a few times for short periods but if I gave it much throttle it'd bog out and shut down. Then after a few tries it finally just wouldn't start again. It defiantly had that spark knocking rattle to it when it did run. Oh yeah, and it was backfiring out the carb too... that was while it was still running before it shut out though. The boat has been used weekly this summer and this is the first problem!

Any thoughts?

I'm in the process of ordering all new tune up parts right now...

 

[Don S]

Re: 4.3 Will not run!! Help!

Do you have spark?

Do you have fuel getting to the carb? Accelerator pump working and pumping fuel in the the carb if you operate the throttle linkage?

 

[mrnmrskyle]

Re: 4.3 Will not run!! Help!

Well, I just went out and with my limited tools at home (which I didnt' have on the water with me) I have no fire from coil to distributor. there is a little box that plugs in on the port side of the boat (if i'm in the boat facing the front of the engine it is on the right exhaust manifold) what is that.... and what could have caused no fire.... I have a feeling this is a super simple sensor or something dumb..

to me it looks like the early throttle bodied chevys and not really a carb... am i right there?

 

[Don S]

Re: 4.3 Will not run!! Help!

That box on the manifold, does it look like this.



Lots of things could cause no spark. Here is the troubleshooting chart.

 

[mrnmrskyle]

Re: 4.3 Will not run!! Help!

Yes that's it. .. The face of it was broken and it was warm n gooey... And I will follow the chart too

 

[Don S]

Re: 4.3 Will not run!! Help!

Yes that's it. .. The face of it was broken and it was warm n gooey... And I will follow the chart too

Warm and gooey ??? I think you found your problem. You didn't have any overheat problem did you?

 

[mrnmrskyle]

Re: 4.3 Will not run!! Help!

okay, I guess it's actually supposed to be gooey as it is a gel... and it wasn't like hot melty, everything in it looks perfectly fine just the cover that says "thunder bolt" is broken... I don't REMEMBER seeing this... but I may not have looked... I'm going to do your flow chart.

I looked at a boat a year ago that had a 350 mercruiser and advertised as runs great... got there and same problem.. no fire... (hadn't been started in a year.... so i was pissed and left) he had his mobile mechanic come and called me the next morning that it was just some sensor that was dirty and it fired right up.... I hate boats lol... what sensors could cause this?

 

[mrnmrskyle]

Re: 4.3 Will not run!! Help!

Ran to Oriley's and got a $15 GM ignition coil and dropped it in... fired right up.... I hate boats... atleast it broke during a local lake ride and not 15 miles out!