1991 5.8L OMC stalls when warmed up

[G Marg]

Hi there,
this is my very first post. I 'm having some issues with my 5.8L motor. Here' s the story.
After 40 minutes of crusing, it started to stall, but would not die as log as i crusied at idle speed. After a break of three hours, it run fine for about half an hour, until it started again.
Tho above situation happened twice, and before i start changing parts i would like to ask a few things. (i have allready read similar threads and have narrowed the possible problems. (at least i think i have).
1. The motor (1991 584APRRGD) uses a Prestolite BID ignition. I would like to change the coil, but the surface is in bad shape an there is no part number to order, so the first question is, does anybody know which part number should i be looking for?
2. I ' m not quite sure if there is a resistor wire attached to the coil. Does this model work with one?
3. My (ex)mechanic replaced the mechanical pump with an electric one (part number 3858261 ). I can't seem to find any spec. for this. Could it be insuffucient?
Any suggestions?

 

[Bondo]

Re: 1991 5.8L OMC stalls when warmed up

Ayuh,.... I'd start by checkin' the contents of the fuel filter for water...
Then be sure the gas tank vent is clear...

Btw,... Replace, don't reuse the fuel filter...

 

[G Marg]

Re: 1991 5.8L OMC stalls when warmed up

Thanks for the immediate response Bond-o. Will check and replace the fuel filter. Any suggestions for the rest of my questions?

 

[indybleck]

Re: 1991 5.8L OMC stalls when warmed up

Thew vent tube got me last summer, I never would have thought about that till I came here looking for answers.

 

[G Marg]

Re: 1991 5.8L OMC stalls when warmed up

Hi indybleck, i'm not quite sure which vent tube you mean. Could you be more specific?

 

[Bondo]

Re: 1991 5.8L OMC stalls when warmed up

Hi indybleck, i'm not quite sure which vent tube you mean. Could you be more specific?

The 1 that goes from the gas tank to the atmosphere...

 

[G Marg]

Re: 1991 5.8L OMC stalls when warmed up

Ok, that's what i thought! What about:
1. The motor (1991 584APRRGD) uses a Prestolite BID ignition. I would like to change the coil, but the surface is in bad shape an there is no part number to order, so the first question is, does anybody know which part number should i be looking for?
2. I ' m not quite sure if there is a resistor wire attached to the coil. Does this model work with one?
3. My (ex)mechanic replaced the mechanical pump with an electric one (part number 3858261 ). I can't seem to find any spec. for this. Could it be insuffucient?
Any suggestions?

 

[Bondo]

Re: 1991 5.8L OMC stalls when warmed up

Ok, that's what i thought! What about:
1. The motor (1991 584APRRGD) uses a Prestolite BID ignition. I would like to change the coil, but the surface is in bad shape an there is no part number to order, so the first question is, does anybody know which part number should i be looking for?
2. I ' m not quite sure if there is a resistor wire attached to the coil. Does this model work with one?
3. My (ex)mechanic replaced the mechanical pump with an electric one (part number 3858261 ). I can't seem to find any spec. for this. Could it be insuffucient?
Any suggestions?

Ayuh,... #s 1, 'n 2,... I know Nothin' 'bout OMC ignitions,....
I'm just workin' the general motor aspect of yer descriptions...
It sounds like a fuel delivery issue to Me...

#3, ya don't say what it is, but I'd imagine it supplies plenty of flow, at 'bout 4 to 6 psi...
Test it, 'n We'll know....

 

[G Marg]

Re: 1991 5.8L OMC stalls when warmed up

Any ideas about whether there is a resistor wire to the coil concerning a Prestolite BID ?

 

[perna00]

Re: 1991 5.8L OMC stalls when warmed up

In reguards to your questions, the electric fuel pump wouldn't be your problem. When the temp raises on your engine it requires less fuel for the fuel air mix than when cold (cold air = more fuel needed). I'm not positive but I do not believe there is not an inline resistor going to your coil. It should be completely integrated with the coil. What I do know is that electrical components have a higher failure rate after temperatures are higher. If the boat stalls after it gets hot and then will run perfectly after it cools down, it will be with a resistor style winding or computer component (ignition coil, ignition module (not with BID), distributer pickup, ect...) Good luck.

 

[G Marg]

Re: 1991 5.8L OMC stalls when warmed up

After a little searching i found a clogged carburator screen filter and that the resistance of the purple wire from the + coil to the alt. is 182.6 ohms.
Also, when i move the throtle on the carb it doesn't return by itself and that there is some fuel leakage when i move the accelarator pump. Any comments?

 

[120_i/o]

Re: 1991 5.8L OMC stalls when warmed up

I cant help you in the coil department, sorry.
The carb. as you described having a clogged screen may indicate a possible carb. cleaning is needed. Since its leaking that may indicate a bad seal/diaphram, and definately do not want to run that in your boat. You will have to dissmantle the carb for cleaning, and since your going to be in there, you may as well put a rebuild kit in the carb. The kits are cheap, super easy to put in, and will help the engine run smoother. Assuming that is a motorcraft/holly carb., you might want to check to make shure the accel. pump is included in the kit. If not, you will have to buy that seperately. Just my .02 pesos

 

[G Marg]

Re: 1991 5.8L OMC stalls when warmed up

Thanks 120_i/o, yes it is a 4160 holley carb. You think the clogged screen could have the float bowls run out of gas?

 

[perna00]

Re: 1991 5.8L OMC stalls when warmed up

It makes sense to me. A clogged screen would only allow a certain percentage of fuel into the engine. Enough for idle but not enough for the fuel demand of higher rpms. A clog can get worse/better based on fuel flow so it sounds like the most logical solution.

 

[120_i/o]

Re: 1991 5.8L OMC stalls when warmed up

Absolutely a dirty screen will starve the carb. for gas. A new fuel filter would be a wise choice too!

 

[G Marg]

Re: 1991 5.8L OMC stalls when warmed up

Thank you all for your help, i 'll keep you informed, once i fix a few things and test the boat.
In the meantime, any further suggestions is more than welcome.

 

[120_i/o]

Re: 1991 5.8L OMC stalls when warmed up

You welcome G Marg. Let us know when you got her going!!!

 

[G Marg]

Re: 1991 5.8L OMC stalls when warmed up

Will sure do! Thanks again

 

[G Marg]

Ok, i know i 'm not supposed to reply to old threads, but after giving up on the boat for a few months, i thought sharing with the community what the problem was, would be helpful.
The problem appeared to be the wiring harness coming from the electric panel. Just before it was attached to the engine wiring harness at the engine bracket, it was 180 degrees bended.
That caused some of the internal wires to be almost cut and not make good connection after vibrating (or warming up?)

Just for the record, i found it accidentally by stepping on the cable.

Thanks again for all the information.