Bogging, snorting, and just running weird. ???

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Twin Pinzies
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Location: San Juan Mountains, CO

Bogging, snorting, and just running weird. ???

Post by Twin Pinzies »

Hey guys,
My truck was running great when it suddenly started acting like it was running out of gas. (it would bog down and then spring back strong for a bit, and then bog down again). Eventually it just shut off and died but would start back up and then eventually bog and try to die again.

-I first suspected that I had gotten some bad gas or water in the tank so I ran a new fuel line into a separate gas jug with fresh gas. No change.
-Then I thought that perhaps a plug had fouled so I pulled them, re-gapped them, and cleaned them. No change.
-Then I replacing the distributor and rotor. No change.
-Then I pulled the air cleaner and cleaned the carbs. No change.

It will start and idle OK but when I give it gas it will often bog down (like it's running on three cylinders) and try to die... then it will "hickup" and run super strong for a bit... then start to run crappy again intermittently. I can only "limp" around with it right now as it goes back and forth from running perfect to horribly.

ANY IDEAS??? Thanks.
kdiqq
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Re: Bogging, snorting, and just running weird. ???

Post by kdiqq »

When you cleaned the carbs, did you pull the jets out and blow them out? I think you got crap in your main.
1977 Austrian 710M
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pcolette
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Re: Bogging, snorting, and just running weird. ???

Post by pcolette »

Check the fuel solenoid valves. Maybe one is intermittent or quit completely?

I'd also check the spark plug wires for fraying, etc. leading to an intermittent short.
Paul C.
_________
'73 Swiss 710M
'89 Puch 230GE
Twin Pinzies
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Re: Bogging, snorting, and just running weird. ???

Post by Twin Pinzies »

kdiqq wrote:When you cleaned the carbs, did you pull the jets out and blow them out? I think you got crap in your main.
No I didn't pull the main jets! That could be it!
Is it fairly easy to do this? I'll dig into it tonight.

Any other suggestions while I have the engine cover off?
Twin Pinzies
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Re: Bogging, snorting, and just running weird. ???

Post by Twin Pinzies »

pcolette wrote:Check the fuel solenoid valves. Maybe one is intermittent or quit completely?

I'd also check the spark plug wires for fraying, etc. leading to an intermittent short.
Thanks pcolette!
kdiqq
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Re: Bogging, snorting, and just running weird. ???

Post by kdiqq »

Twin Pinzies wrote:
kdiqq wrote:When you cleaned the carbs, did you pull the jets out and blow them out? I think you got crap in your main.
No I didn't pull the main jets! That could be it!
Is it fairly easy to do this? I'll dig into it tonight.

Any other suggestions while I have the engine cover off?
If I get time tomorrow, I will upload the sections of the service manual you need. The sucky thing about carbs is they have so many delicate orifices and circuits in them, if you have any piece of anything in your fuel system, it will likely require a carb rebuild so you can tear it all the way down and be TOTALLY sure it's all clean.

When you said you ran it off a gas can, did you bypass your fuel filter? Could you see fuel moving through the line when you tried to crank it?
1977 Austrian 710M
Twin Pinzies
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Re: Bogging, snorting, and just running weird. ???

Post by Twin Pinzies »

No I didn't bypass the filter. It is a brand new see-through style. I could see the fuel moving through the line as it ran off the gas can.

Damn. I was hoping that I didn't need a rebuild. I'll try cleaning the main jets first to see if that does the trick.
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4x4Pinz
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Re: Bogging, snorting, and just running weird. ???

Post by 4x4Pinz »

when was the last time you checked your fuel lines and pump. A small crack in the fuel line will give the same results you are having. Also the fuel pump diaphragm will give similar results as it starts to fail.
The next area I would look at is the amount of play you have in the distributor shaft. The upper bearings are not being maintained in the manner the book describes and they are prematurely wearing out. The slop will cause the truck to run poorly as the spark gap changes constantly since the rotor does not stay in center of cap.

In the 12 years and many, many thousands of miles I have put on my pinzgauers, I have only had to rebuild the carbs once. It is my belief that owners play with their carbs WAY to much. There are folks that rebuild them every couple thousand miles, though it is not necessary. These are usually the same folks that have lots of trouble with their carbs as they won't leave them alone. Yes they need adjusting on a fairly regular basis but a complete rebuild is usually not the issue.
Look else where before playing with the carbs.
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Jimm391730
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Re: Bogging, snorting, and just running weird. ???

Post by Jimm391730 »

And check your distributor for sticking advance weights. The rotor should be able to turn against the spring return; if you can't turn the rotor and feel spring pressure then they are probably rusted in place. Just happened to me, and gave similar poor running as you have described.
Jim M.
712W and 710M
Twin Pinzies
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Re: Bogging, snorting, and just running weird. ???

Post by Twin Pinzies »

UPDATE:

After checking my fuel lines and fuel pump to no avail (a newly rebuilt pump and newish hoses), I swapped out the ignition coil ... and it solved the problem!
I was clued in when the engine starting acting boggy and backfiring as soon as I pulled my finger off of the start button.
The starter made the engine run but when released, the engine would immediately try to die.

Thanks again for all of the input. You guys (and gals) rock!
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