Fouled spark plugs?

[MoParJW]

If oil is getting in your cylinders through the pcv system, an ''oil catch can'' will help in keeping your plugs (and valves) clean.

[rikubot]

I really appreciate the input. Funny thing is I've also spent a lot of time at idle tuning and fixing vacuum leaks, and I'm sure i had the mixture way to rich for a while too. This is the first carb I've ever tuned so I'm sure I have been doing a less than perfect job haha.

I'll slap myself just for the stupid question, but is the PCV valve the thing on the cover going to the carb?

[crj1968]

Yes. 

[XH29N0G]

.

[rikubot]

I borrowed a compression gauge from a friend today and could only check the passenger side before it got dark. I got around 75 on all four, and I only pulled one plug at a time and didn't have the carb all the way open, which I just read was wrong. Would doing this the correct way make that big of a difference from the high numbers I've been reading online?

[rikubot]

Thanks for the graphic! I'm not quite sure how it works though...

[myk]

.

Hmm....mine is set up so that the PCV goes into the carb, and the breather goes into the air cleaner.  Is that right?

[rikubot]

That's exactly how mine is set up as well.

[XH29N0G]

I borrowed a compression gauge from a friend today and could only check the passenger side before it got dark. I got around 75 on all four, and I only pulled one plug at a time and didn't have the carb all the way open, which I just read was wrong. Would doing this the correct way make that big of a difference from the high numbers I've been reading online?

75 seems very low to me.  It is not clear to me if the 75 was just the first bump, or was after 3 or 5 or after it stopped rising. I suggest redoing the check for all (the others will be a reference) with the carburetor wired open, paying attention to how much it rises with the first bump and then getting the final reading when it reaches a maximum.  If there is a difference then people here can guide you through other tests.

Other thoughts:  From what I understand, there is an effect of the carburetor being open, but my guess is probably not all the way to 75 psi.  I read 120-130 psi on an engine that I know had no more than 135-140 psi so I don't think it is too much of an effect.  I have also read high readings pulling only one plug, so I think that is OK unless it really slows the cranking speed.  Cranking speed apparently can have an effect.

One other important thing.  If you get a crazy reading, check the gauge to make sure it is reading correctly.  (Or buy a second one to check against.)  I checked mine using a bicycle pump and it would probably have taken less time to buy a second one.

[rikubot]

I probably should have cranked it longer. I am certain I didn't do a full 3 second crank of the motor. Ok, so when I get off work I'll do it again. I'll take all plugs out just in case that effects the cranking power, and wire the butterflies open on the carb. I might go get another compression gauge as well. How tight should I screw in the gauge? I didn't go to tight because I was afraid to chew up the O-ring on my buddy's gauge. Again thank you all for all the advice so far!

[PlainfieldCharger]

I probably should have cranked it longer. I am certain I didn't do a full 3 second crank of the motor. Ok, so when I get off work I'll do it again. I'll take all plugs out just in case that effects the cranking power, and wire the butterflies open on the carb. I might go get another compression gauge as well. How tight should I screw in the gauge? I didn't go to tight because I was afraid to chew up the O-ring on my buddy's gauge. Again thank you all for all the advice so far!

Get a battery charger on your battery too..

[crj1968]

.

Hmm....mine is set up so that the PCV goes into the carb, and the breather goes into the air cleaner.  Is that right?

Yeah it's right- the image just shows PVC going into intake...same thing

[XH29N0G]

I probably should have cranked it longer. I am certain I didn't do a full 3 second crank of the motor. Ok, so when I get off work I'll do it again. I'll take all plugs out just in case that effects the cranking power, and wire the butterflies open on the carb. I might go get another compression gauge as well. How tight should I screw in the gauge? I didn't go to tight because I was afraid to chew up the O-ring on my buddy's gauge. Again thank you all for all the advice so far!

Get a battery charger on your battery too..

Also watch the needle bump up until it stops rising.  You can to 4 or 5 bumps, but that is also close to where it stops rising.  Good luck.  The gauge needs to make a seal.  If you tighten it in by hand until it stops, I bet it will seal fine.   I don't think it needs to be tighter.  That is all I have done.  I would only get another gauge if you want one for yourself or you suspect a problem with the one you are using. 

[c00nhunterjoe]

Engine at operating temp, All plugs out, throttle wired wide open, fully charged battery. 1st needle bump should be minimum 90 psi on all cylinders. 5 bumps on each cylinder max. Report back numbers.

[Sublime/Sixpack]

Engine at operating temp, All plugs out, throttle wired wide open, fully charged battery. 1st needle bump should be minimum 90 psi on all cylinders. 5 bumps on each cylinder max. Report back numbers.

This 

[rikubot]

Ok thank you for the checklist. Any tips on not burning my hands off?

[c00nhunterjoe]

Most headers shouldnt be a big deal. I can have all 8 plugs on the fender in about 5 minutes with my $100 set of hedmans. Some use a ratchet with no extension, a few use a short extension, and 3 use the plug socket and a stubby wrench.

[rikubot]

I see. I'm more worried about threading in the gauge to be honest haha. It was kind of a pain in a cool motor. Should I just man-up and figure it out?

[crj1968]

I see. I'm more worried about threading in the gauge to be honest haha. It was kind of a pain in a cool motor. Should I just man-up and figure it out?

Gloves.    

[rikubot]

Haha I'll try my best. I'm damn near useless with my gloves 

[XH29N0G]

The headers will cool quicker than the engine.  Other's may say otherwise, but I think it is OK to wait for them to cool a little first.  I also doubt the 75 reading is just a warm/cold phenomena, but could be wrong.   I used those work gloves with Velcro from some place like home depot, they seem to give enough dexterity to manipulate and warning before burning.  Good luck

[Sublime/Sixpack]

At least have the engine fairly warm when doing the test.

[rikubot]

Got it checked up today after work. Thanks for all the help guys. My numbers were all around 95lbs give or take a few lbs per cylinder. I threw new spark plugs in it while I was at it. 

[XH29N0G]

Some quick clarifications:  

   What is your altitude? 
   How fast was the engine turning over?
   Is this for 5 or more bumps of the gauge, or just the first rise?  
   Was it 95 for all 8 cylinders?  If so was there any variation?

If it is 95 and there is no other reason for a low pressure (cranking or altitude - I think this could be equivalent to ~110-120 if you are in the mountains) , I would check the gauge and then see what others say.  

[rikubot]

Looks like my altitude is 4692 feet. I think the gauge bumped up at about 1 Mississippi. The driver side was closer to 97 consistently while the passenger side was closer to 93 consistently. How do I check the gauge for accuracy?