[kkettelhut]

ok, loving the snow, but...

A couple days ago during the last good dump I was casting some snow when the engine power dropped out. Started backfiring and running real rough. Backed off to idle ran it up the drive and parked it. The Carb (C-275369) was pissing gas, first thing next day went out and bought the overhaul kit, bowl gasket, bowl baffle, needle valve, seat, bowl nut gasket. took carb off, cleaned it through and through, set the float to 11/64ths installed new parts / gaskets. Set idle and main to presets for K321

Then had intermittent spark and wouldn't start, (has been running rich, lots of black smoke at start up and plug was carbon fouled). Checked points - Good, Tested coil - good, tested condensor with digital multimeter (certainly not best way to test but all I had) -so so. Bought new plug and condensor, and she fired right up. Adjusted idle easy as can be. Let it run for a bit, then adjusted main, didn't really get much change at all. Started casting some snow and started backfiring, and running real rough. Pulled air cleaner and gas pouring out of carb again. adjusted main all the way down let it burn off gas till starting to stall, then opened up 1 turn, and started backfiring again. Still runs great at idle.

What am I missing, both needles looked good, not deformed, not cloged. My main needle has the one hole down at end, the two middle holes, and the four up top for the idle. Fuel appears to be coming up out of the emulsion tube at throttle, but that is normal right? Just not sure ofthe rate it is coming out at. Before I throw more parts at it (main needle and emulsion tube) thought I would ask Pullingtractor, and the rest of the gang. Did it here instead of a PM so we all could learn.

 

[kkettelhut]

oh, yes also, but unrelated. my head is warped or bolts are stretched, as I get some blow by at high throttle around a few of the bolts. That is an issue for down the road though...

 

[mikebramel]

I had the same problem too. Very obvious even when turning over. Headgasket

 

[kkettelhut]

Brand new headgasket, properly torqued, did it... still leaked. took off added some high temp sealant, re torqued, still did it. Thus thinking warped or stretched. come better weather and downtime for tractor, will repull head to check. Then have head shaved if I have the clearance. Certainly a secondary issue to the Carb at this point, unless it is causing it

 

[Hydriv]

Sometimes....the only way to cure this problem is to dismantle the carb and soak it thoroughly in true carb cleaning solution for at least 24 hours. Then you have to use fine wire to "rod out" every single passage in the carb and then follow that up with rinsing in clear solvent. You then use compressed air to blow all passages clean and dry.

It only takes a tiny spec of dirt to lodge deep into a passage way to cause all kinds of grief.

 

[kkettelhut]

ok, going to take it apart again, re soak, re clean, re blow out, re check float adjustment, recheck needle and seat . . . then see what happens. I realized while talking to a friend that though I said it was back firing, its not "back" firing out of the carb, but rather the fuel isn't completely combusting and its "firing in the muffler". That might change the symptoms a bit. The carb is just serving up way too much fuel when I open the throttle, but idles beautifully.

 

[Billygoat]

The head gasket may be related to the carb issue. If the head gasket is leaking not only does it blow out , but also sucks air in when the piston drops. This could cause a lean condition in the combustion chamber causing back fire. I had a problem with one of my Harleys that had a leak and pretty much did the same thing, backfires and gas being pushed back out of the carb instead of being drawn into the combustion chamber. Fix the head/head gasket first then work on the carb. I don't see any way a carb can be set up properly unless the engine is doing it's job correctly.

 

[Kenc]

I didn't see any mention of a new fuel line an filter.

It is my standard procedure on a carb cleaning project. A nasty line and/or filter can just ruin a nice clean carb.

new fuel line/filter, don't leave home without it!

Or, priceless, depending on the year of the commercial.

 

[kkettelhut]

Did replace the fuel line between pump and carb with the cleaning. Did the filter and line between it and pump couple months ago, but will toss a new one in as it can't hurt.

 

[mastifflawyer]

Do not forget the fuel line from the tank to the pump.

 

[InTroubleAlltheTime]

I didn't see any mention of a new fuel line an filter.
It is my standard procedure on a carb cleaning project. A nasty line and/or filter can just ruin a nice clean carb.
new fuel line/filter, don't leave home without it!
Or, priceless, depending on the year of the commercial.

My operators manual for the 1986 446 (actually 18 hp Linamar) recommends changing the fuel filter every 500 hours. Seems like a lot of hours. I don't think I am doing that many hours annually. I have been changing the fuel filters at least annually. Also replaced a cracking fuel line as preventative maintenance. What are the thoughts on frequency of changing the fuel filter as part of standard maintenance?
:222: :446: Best Regards, Rich

 

[skiveller]

Did replacing the fuel line and filter solve your problem. I find that I was experiencing the same problem this winter after lots of hard use. But I am new to the tractor, (mine is 1971 444) and know that I was not operating it well at the time of problem.

Ran her this weekend under load and found that I need to back the low idle needle adjustment in to run with out pushing to much fuel to the muffler.

BTW, I live in Brunswick, so we are pretty much neighbors.

 

[kkettelhut]

no, it didn't solve the issue yet, but thankfully I don't need to blow any more snow this season. I bought a can of carb soak at NAPA, just have not had the time to do the tear down again. Life keeps getting in the way. I plan on pulling the carb, pulling the head - to check for flatness and or shaving if it needs it. I need to solve the blow by issue on the head bolts. Do some more renovation work on some of the rougher parts at the same time. I got the crapsman working so I can mow and tow the garden cart for my yard chores. Slowly but surely I am renovating the Case, then a deck, PTO, tiller, sleeve, etc... lots of desire, not a lot of time or money to do same. I am told there is a 222 with a caster at the junkyard at the end of Allen range rd in Freeport that I need to go check out sometime

 

[Rockdog]

Hydriv is right about cleaning. Excessive fuel such as you mentioned sounds like a float or needle and seat.