Chrysler ind. engine?

My combine has a Chrysler 318 engine and it runs
like crap. It's been sitting for several years so
I'm sure that's what the cause is, but where to
start. It coughs and backfires through the carb
when you give it gas and under load. Under load it
will only run with the choke fully pulled. It's
not the float tho because I had to replace that
and I adjusted that. Is that more likely a carb
issue or ignition? Also it has a vacuum chamber on
the side of the distributor, but it's not hooked
up. It has a factory plug where the hose should
hook to. Doesn't that need to be hooked up? I'm
wondering if someone replaced the distributor and
never completed the hookup.

Dad had one in an oliver combine but I don't remember a lot about it. Sounds like a carb rebuild is needed. Are you familiar with accelerator pumps? I will have to think on this bone a bit.

There is no accelerator pump on this one.

Make sure the weights in the distributor are free, I doubt if the vacuum advance was used at all. I would say you have a lack of fuel problem. Check the tank, and work your way up to the carb.

I should have said that, I already got that far. I replaced the sediment bowl and installed an electric pump and have good flow through the float and seat. It is after that if it's a carb issue.

I expect you checked but are you %100 sure you got all the passages in the carb cleaned? fuel is fresh?plugs are clean and gapped right? does it have carbon core wires? and are they good? carbon track in dist cap?coil good?

Some things to check:

On the backfiring, sounds like too lean. This can be a carb problem, as in restricted fuel circuit, vacuum leak, burned out manifold (exhaust heat crossover). If it's been run for an extended time backfiring, the ventura in the carb could be melted.

If the backfiring is a steady popping that increases with throttle, that can be an exhaust valve not opening.

Can also be ignition related, bad plugs, cross wired, carbon tracked cap, bad plug wires, points out of adjustment or bad, condenser bad or loose (if equipped), worn distributor bushings, stuck advance weights, retarded timing.

The vacuum advance that is capped off, I've see that done on industrial engines. It's not really necessary on an engine that runs under heavy load. I think the factory does that for 2 reasons, they didn't want to make a special distributor without one, and they figure it would be short lived, soon fail and become a vacuum leak. You can connect it if you like, I would test it first. It won't make that much difference. If you know the timing specs and have a light, then use them. otherwise just use your ear and judgment, set it where it runs good, starts good and doesn't rattle.

Even the best tuned engine will not run right if the compression is not there. If it idles good, good chance the compression is good. If there is a miss at idle, it's not ignition related, and there are no vacuum leaks, check the compression, look the valve train over, check the backlash in the timing chain.

Had more than one 318 in my life, and timing chains do wear , get sloppy , and hurt performance.

Check the ignition resistor.

Allan

Stuck or sticky valves and not closing properly so flame goes out of chamber through the partially open valve and out the carburetor.

Co-worker had one in a Case run like crap, discovered the rocker assembly on one bank too tight, shimed it up, ran great after that.

Jon ..either rebuild the carb ,or get a brand new one ,, you will be money ahead ,,, carbs are cheap compared to the cost of gas ,,everytime I did that I was so pleased with the result kikin myself for not doing it sooner

I should also add that the back firing only happens on acceleration. If you feather the throttle and get it up to rpm it runs smooth. It also idles smooth. It does seem to run out of gas under load tho. So I may have a passage blocked yet. Guess I'll take the carb off next and clean it.

Take the top cover off and the jets are in the bottom of the bowl. All the crap settles there and plugs them off. Two big screw type plugs in the bowl that when removed allow you to clean the jets out. Points gap needs to be correct also.

waking up sleeping gassers are a real pia to me. LOl. you are probably doing this , but ,, use lucas fuel stabilizer/cleaner/upper cylinder lubricate ,, and or seafoam in the gas , and heet ,. nuthin worse when you need to go get a job done ,, and thedamthangis stammerin and stutter-puttering while you are stroking the choke and beggin it to run .. btw lub wd-40 up your choke cable ,,. never had one yet around here that worked with ease when it wandered up my driveway

A lot of good info here, I will add I have been around a few 318 ind. I think they are cammed different and very cold blooded till they are thoroughly warmed up, but sounds to me that it is running lean. If you are using our Mn. crap gas you may have to drill the jets out about 5 thou. I have done this on some fixed jet carbs over the years with great results. I use non alcohol gas here on the farm for about the last 4 years and ALL fuel related problems have magically dissapeared. Everything runs so nice and has some HP. back, Good luck with that nice old Case combine!!

Take the carb off and put it in the smallest bucket that it just barely fits into that will cover it completely, then fill the bucket Gumout carb cleaner, not the spray stuff, but rather the pour stuff that comes in pint cans that covers the carb completely. Swish it around to make sure that it filled around the float as well because the pivots on the float that hang it from its horizontal rod (mounting) are no doubt gummed up to, and can or will cause the float to stick eventually, causing the gasoline to overflow out the vent on top of the carb. Let it set a few minutes, swish it around to get the cleaner flowing past the jets, through venturies, clean orifaces. Lift it out, turn it upside down so crap empties out the bowl vent as well as create a rinsing flow past the jets, venturies, orifaces, dunk it again. Do that a few times. That should set you up pretty good on the carb. Store the carb cleaner in a glass jar like "Ball" for canning to use at a later date.

Might have crap inside the distributor cap as well. Terminals to the plug wires might be corroded where the rotor passes. Vacuum hoses dry rotted, need to be replaced. Be careful of the valve train too. Valves have been seated, some left open, valve stems might be rusty and trying to pass through tight guides and might tear up the seals above the guides. When you get it running, don't race it. When you wake up in the morning, you don't bend over with your eyes still half shut, put on a pair of running shoes and sprint down the road do you? Get it running good, let it idle awhile, ease into it. The 318 is a simple, durable engine that has been around as long as some of us have been alive, longer to others.

Good luck.

Mark

We have two Chrysler 318 industrials were I work that are in tugs. One of the biggest improvements we made to these was installing gm hei distributors. Not sure on how much you use this but it makes a world of difference in starting and running. Does away completely with the weak Chrysler ignition system.

If it"s wired the same as in a car, it would fire while cranking, then quit once you let off the starter.