Sticking Exh Valve

For a whole bunch of reasons I DO NOT think its a carb or a mag problem but my unstyled B isnt running to suit me and I wonder if a sticking exhaust valve is the culprit??? When I rebuilt it some years back the shop did a valve job and I think maybe???? one of the exhaust guides was a wee bit on the tight side. Once after a longgggg gg slow idle a valve hang open which I attributed to how unstyled B"s dont get much oil up in the rocker area especially at slow idle PLUS it was very tight in its new guide.

Anywho heres how it acts and carb adjustments or timing etc etc dont seem to affect it. IT WILL NOT RUN SMOOTH AT A CONSTANT RPM. It will be fine a while but then intermittently miss out and spit out the stack. It DOES NOT smoke black or blue, it and the carb etc have been overhauled and shes not runnin over rich or too lean. It just has an occasional miss and makes a spit/small pop you hear out the stack and the governor bumps the throttle whereby she will not maintan a smooth constant RPM for an extended period. ITS NOT that shes hunting or revving up n down and surging or like, the governor is bad or shes starving for fuel etc, its just that she will run smooth at constant RPM a while but then miss n spit causing the governor to bump a time or two and then she settles back in smooth a while. I cant say she backfires or pops out the stack and maybe the spit and governor bump is caused by something other then a sticky valve and the noise is just normal after a cylinder misses a beat?????

HOWEVER occassionaly she will almost like start to die (worse then an intermnittent miss) but then when she catches A VERY LOUD POP N BANG N BACKFIRE EXPLOSION EXITS THE STACK.

It really dont have that many hours on it since that valve job and I think it had a tight guide and she NEVER pops or spits back out the carb ONLY THE EXHAUST.

I threw in some tranny fluid and valve cleaner and am trying to let her run a lot hoping a valve stem n guide may free or polish or clean up.

It will take spells n run at constant RPM with no misses or spits but then she misses a bit n spits and the governor bumps before she may settle back in smooth for a while.

Sooooo oooo you guys think it may be a valve sticking????? ????? or something else????? ??? I havent checked the lash lately I may tomorrow. Again it was overhauled and has a ton of compression and the rockers n valve shaft was rebuilt n theres no black or blue smoke and the carb n its adjustments are fine and she has a hot blue spark and fresh Autolite 3077 plugs. It ought to pop pop pop pop at constant RPM and it does a while but then she will miss just like one cylinder one firing (i.e. very brief) which makes the spit sound.

NOTE..... ... When I say spit I dont mean she blows or pops out the stack I mean more like its a brief miss and that in turn makes the spit/miss sound and the rpm fluctuation till she settles back in again. Lets just say she has an occasional miss maybe !!!!! !!!!! !!!!! !! I guess it could be an ignition problem but I doubt it as it acts the same with different mags or new or old plugs etc and I dont think its the carb cuz BOTH needles adjustments respond as they should n theres no exhaust smoke of any color SHE JUST WONT RUN SMOOTH N STEADY AT CONSTANT RPM AND POP POP POP POP LIKE SHE SHOULD GRRRRR RRRRR RRRRR RRRR Its more lile pop pop pop spit pop pop pop miss etc etc grrrrr rrrrr rrr Tomorrow Im gonna remove the throttle rod n manually hold the butterfly to see if she will run smoth in case the governor is acting up n bumping the throttle occassionally.

Im of the opinion the unstyled B"s dont get near enough oil on the rockers so the valve stem n guide may like never wear in ?????

Opinions appreciated, thanks in advance

John T (NOT a happy camper)

John T

Now a few things I've noticed to help settle down some tractors. Alot of people think the idle speed is set by "being able to count the fan blades" NOT SO most of these are only to idle down to 500-600 rpm Some of the carb. rebuilders are not applying sealer to the little brass screws and getting them tight enough. This will cause huge fits !as it sucks air. If all else fails try opening up the gap on the spark plugs. I've heard tales of ole of setting them with a nickle. This is very wide and I don't go that far,but I have noticed some improvement on a few by opening the gap up. I suppose they could of fit the valves too tight as most machine shops set this stuff up to modern specs. which are far tighter than these old tractors were originally made to.But I would also think that if you had tight valves it would really show up bad when hot and working under a load ? I would think it would just end up sticking open and makeing a steady miss ? Good luck with it,but it may just be your expecting too much out of it ? Also heard of some carbs. not being made as good as others from new or just plain worn out ? so maybe another carb. would be drilled different and run differently ??? This is what the dealer told my uncle a long time ago on his 1952 B when they sold him a new carb. and I have the tractor now and it sure does run good !!! I don't have the old carb. to try back on it so who knows ????

Buttttt tt I find it hard to believe a valve set just that much overtight could have caused all that????? ???? but once I loosened it now shed muchhhhh hh better so ????? ???

As far as carbs and your remarks concerning a sweet smooth slow even RPM idle, Ive NEVER seen an unstyled B idle as well as an A or G and I think thats due to the MUCH heavier flywheel on those what ya think??? Ive had them that will idle so slow the mag starts winding n tripping n snapping n clicking (under 250 RPM) which isnt good for the mag or tractor but is impressive

Next thing Im a gonan do is use 2 or 3 plug washers under my Autolite 3077 (hotter deep reach side wire elecrode plugs for the unstyled) to try n make them run hotter. Despite good hot mags n good engines n carbs set way lean etc IVE NEVER pulled one of those plugs that had the nice warm gray color and hope to before I die lol. Buttttt tt as long as we baby them and idle them and parade them and dont work them hard as they were designed for, I guess they are gonna blacken depsite how good the carbs and ignition are grrrrr rrrrr rrrrr rr

Yall take care, the patient is much better this morning (wonder if a tight valve lash could have made that much difference????) and maybe an unstyled B will NEVER run/idle quite as smooth as an A or G ???? heavier flywheel???

John T