1987 4.3L v-6 OMC Cobra poorly running

[Faerbairn]

Hi,

I need help troubleshooting my 4.3L v6 omc cobra. The symptoms are erratic idling. It sometimes stalls when I punch it. Last time I was out we were doing about 30mph steady and then it all of a sudden bogged down and seemed like it would stall if I did not nurse it back to the dock.

I pulled the plugs and they looked pretty good. I checked them to the book and it suggested poor ignition, fuel/air mixture not set right, and or too low a temp range on the plug. I have the correct plug per the manual.

How do I determine the fuel / air mixture is set properly? How do I check if the coil is good? The plugs and wires are new. How do I check the distributor? I have the manual, but I need a little more guidance.

Thank you for your help.

 

[JustJason]

Re: 1987 4.3L v-6 OMC Cobra poorly running

A/F mixture is not your problem(or not the main one)
The coil coild be a problem. Check it when it's hot with a multimeter. Specs and procedure is in the manual.

When was the last time the engine had a complete tune up?
Have you checked the compression yet?

 

[slasmith1]

Re: 1987 4.3L v-6 OMC Cobra poorly running

another place to start would be to ask the question when was the last time your fuel filter/water seperator was changed.

 

[Bondo]

Re: 1987 4.3L v-6 OMC Cobra poorly running

A/F mixture is not your problem(or not the main one)

Really JJ,..?? My 1st thought when reading This;

The symptoms are erratic idling. It sometimes stalls when I punch it. Last time I was out we were doing about 30mph steady and then it all of a sudden bogged down and seemed like it would stall if I did not nurse it back to the dock.

Is that the Fuel Filters are Full of Crap,+ it's migrating into the carb....

Which is why I'd suggest Faerbairn should do a Full,+ Complete Tune Up,+ Service....
Especially changing,+ Checking the Fuel filters... Inspecting the contents for Water...

 

[JustJason]

Re: 1987 4.3L v-6 OMC Cobra poorly running

Really JJ,..?? My 1st thought when reading This;

Yeahp...I did say that, that because of this....

Last time I was out we were doing about 30mph steady and then it all of a sudden bogged down and seemed like it would stall if I did not nurse it back to the dock

The A/F mixture doesn't effect anything off idle. Although you are absolutely correct in it having cause erractic idleing. (but you know all that already )
I guess it's very true if the total A/F ratio is off, not talking about the adjustment screws, but like you say, junk in the filter.

Faebairn. A full tune-up consists of New plugs, cap, rotor, points&condensor, plug wires, ALL fuel filters (you may have up to 3, but at least 1 on your rig), setting the base timing, checking for advance, setting idle mixture and then finally setting your in gear idle rpms.
On a side note. If you've never had a compression test done, you may want to spring for a tester and check it first. Hate to see you throw tune up dollars at a boat if your fighting a bad cylinder issue.

Top of the mid' morining to ya Bill

 

[Bondo]

Re: 1987 4.3L v-6 OMC Cobra poorly running

Top of the mid' morining to ya Bill

Ayuh,.. Right back at ya Jason,.... Sleep in this mornin',..??

 

[JustJason]

Re: 1987 4.3L v-6 OMC Cobra poorly running

Ayuh,.. Right back at ya Jason,.... Sleep in this mornin',..??

Yep

No boat work for the last couple of weeks, and I suspect I won't be skiing yet for another 2.
That's when the real fun begins.