popping above 2700rpm

[kyhunter89]

sbc, flat tappet cam with 5k miles. Was runnning fine, timing chain cover started leaking and I changed it a week ago, it'd got two quarts low before I realized it was leaking. I pulled all the plugs one at a time and every one made a difference. It launches hard and picks up hard till 3k ish then small pops out the exhaust.

I've played with the timing already. My plan is change all the plugs and run out some of the gas and refill it to make sure it not bad gas.

Have I wiped a cam lobe?

[Deaf Bob]

If it starts popping at lower rpms...I would think so.. Are you running ultra stiff valve springs? .. Check the exhaust hole in the intake side (where exhaust goes under the carb to warm the charge)..carbon build up may push the pushrod sideways enough to wipe out a lobe..

[Barry Donovan]

be sure full warm, see if it goes away.
you may have a precise fuel error, leaky coolant...oxides.

the simplest common one is oxides.

[redneckjoe69]

kinda sounds like you might be having a fuel delivery problem?

[Scott Liggett]

If it was backfiring through the carb, I would think you have a lean out condition. Like fuel delivery. But, since you said it's popping through the exhaust, I wondering if your mechanical advance in your distributor is stuck and not moving as the engine revs up.

[STINEY]

Remove gas cap, try again. Hey, it's easy to try..... Swap coil. To my experience most fuel issues are really primary ignition.

[kyhunter89]

Its not really a back fire or loud pop, just multiple little misses I can feel and hear. Still havent got to change plugs, hopefully tomorrow if the weather eases up. I've been wanting to swap distributors anyway, this is a great excuse. I need to check my fuel pressure too I guess.

[Dan Barlow]

Are you absolutely sure you got the timing dots lined- up? I think its timing. Switch distributors if you know the chair / gears are fine . Drop it in straight upand just play with.it. I thought I had mine right but it was off on the retarded side. Mine ran great but wouldn't stop running unless I dropped the clutch withy foot on the brake.

[kyhunter89]

It was one of the plugs, I changed them all and problem solved. Thanks guys.

[DanStokes]

I was going to suggest:

A) Shift at 2600 RPM
B) Take the mufflers off and dump the Orville Redenbacker's out.

Now that it's fixed I can tease about it.

Dan

[kyhunter89]

I drove 100ish miles last night to and through bowling green and back. Didnt have a hiccup, and I resealed the leaking intake bolts so I hopefully can make to motor presentable and not oil covered.

Dan you can insult me before its fixed. I'm hard to get down and know life goes on. Just today I destroyed my new lawn mower's engine 20 minutes after I bought it, never even cussed. Gotta stay positive.

[Beagle]

the biggest insult is having to finish mowing the lawn with the old mower. Been there, done that, probably still have the crank so bent that it had to be cut off to remove the sump (oil pan in Briggs speak).

[DanStokes]

I say take the mower back and tell them it doesn't work. Worth a try.........

Dan

[Scott Liggett]

I drove 100ish miles last night to and through bowling green and back. Didnt have a hiccup, and I resealed the leaking intake bolts so I hopefully can make to motor presentable and not oil covered.

Dan you can insult me before its fixed. I'm hard to get down and know life goes on. Just today I destroyed my new lawn mower's engine 20 minutes after I bought it, never even cussed. Gotta stay positive.

I waited two whole weeks before chopping concrete with my new mower. or my dad's new mower that I was forced to use as a kid.

[Barry Donovan]

It was one of the plugs, I changed them all and problem solved. Thanks guys.

that was easy.
I was just hinking of new fuel pumps with machinist oil residue.. that heavy stuff splits up through a carb near 3000 rpm.

nice burp and pop.

glad its fixed.