The firing order for this engine is 1 .5. 4 .2. 6 .3. 7 .8.

Its hitting on every other cylinder. 1,4,6,and 7. The other 4 don't even get wet. We have tested all spark on the dizzy and checked all wires. We also checked the spark at the plug. All looks well except for the 4 cylinders that don't fire.. the new spark plugs look like they never fired. I have a Holley 4160 and my engine intake is stock. I checked the compression in all cylinders and all measured 150-155. I have tripple checked the firing order and wires. Here is the kicker... it starts and runs
not well but it goes on the 4 cylinders. I don't know what to do next, please help. Just got truck all together after 4 1/2 years and oh well, this happened.

 

I bet you have a dual plane intake manifold and gas is getting to only half of your cylinders. You need a carb kit or a new carb.

 

Thanks for the reply. I rebuilt the carb earlier. But I will again.
The last thing I did to the carb was install the power valve check ball kit
from Holley. I wonder if that would have anything to do with this problem? or did I screw something up.

Is there a drawing somewhere of a dual plane intake manifold somewhere I can refer back to?

 

Looky at this pic. Note how 1,4,6 & 7 all feed from the "top" set of runners, which are feed by the two right (passenger) side barrels.

You have one side of you carb clogged.

Second instance of this within 3 months.

Google Images

 

85e150six4mtod - sorry I could not see the image. How do I know (check) that the left(drivers side)
barrels are clear? Also, could you please send it again or what do I do in google image?
Thanks

 

Basically the image shows a dual plane intake manifold. If you follow the path of the intake runners, it shows that all the cylinders that ARE firing are being fed by one side of the carb, and all the cylinders that are NOT firing are being fed from the other side of the carb. You've got carb problems.

 

Trying again.

http://www.hotboatpics.com/pics/data...CJIntake01.jpg

You need to pull your carb down and check for contamination, plugged jets, etc.

 

What led up to this problem ? Was it just running fine then quit running right or was some work being done on it ?

 

Could be a RIM problem too.....

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(Rag in manifold)

 

Man, that brings back memories......
I don't admit this one to too many people, but it happened 10+ years ago and luckily no harm was done.
I was a forklift mechanic in a factory that had a fleet of about 30 lifts. We had a fairly large Caterpillar diesel forklift in the shop that (can't remember what the problem was but) we had to have the air cleaner unhooked while we started it, revved it up for a few seconds, make some adjustments, and then shut it off. As I remember, we had to do this a dozen or more times to get the right adjustment. The exhaust pipe ran behind the back vertical cage support and pointed straight up. Each time we shut it off, I would stuff a rag in the tube between the air cleaner and the intake manifold. In the intense pressure to get the machine back into production quickly, there was one time that I forgot to pull the red rag out of the air cleaner/intake manifold tube.
I started it up, revved it up and suddenly there was that hiccup that the engine did as it gulped down the red shop rag. It was too late to shut it down and suddenly there was a bunch of red confetti coming out the exhaust pipe on two other guys and myself. I got really lucky as there was no engine damage.
I quickly got a broom and swept up the hundreds of little pieces of red shop rag that had fallen on the floor. The boss never found out about it.......

 

I watched two guys kick, push and pull a dirtbike around a parking lot for 20 min. once--rag in the cylinder port. No damage done. Your's is a better story.

 

Well, to all those who want to know what the problem is and was....here it is,
Thanks to Kruse. I do have a dual plane intake and thanks to all the rest..... I tore down the carb twice in the last 3 days...it was and is a carb problem.... at idle there was no gas coming into the drivers side intake and very little at idle to 1500 rpm but gas was running
when the RPM's got above that. I cleaned that carb until it was highly polished inside and out with every kind of cleaner I had in the house. Alas, no good. Now I got to get another one so off to the store we go.

Thanks for all the advise and BTW, I did check for that "RIM" hoping thats what it
was but not today.

 

Hey, you get your money's worth on this site.
Look on the bright side. You could've had a single plane intake on there and you would have possibly fought that problem a long time before you found it.

 

Sure do, at least All you folks are helpfull.
Thanks again, until the next time