Farmall 450 Gas Engine trouble HELP!! :)

OK, I will try and be as specific as possible on my issue.

I have had this tractor for the last 5 years and it has ran very strong, no backfires, purrs like a kitten. Well last week, I was not doing anything special with the tractor, was just moving implements around the pasture. The engine started to me like it was misfiring. Lost a bunch of power. The engine would almost die, then it would rev up a little and sputter. It would never die, just seemed very close to dying, before coming back to a little life. I checked the distributor, and scrapped the deposits on all four terminals, that seemed to help a little for about 10 min, then it started all over again. I removed the little plug that is above the carb, that goes to the intake, and a flame shot out and the engine sounded like crap, so I put the plug back in.

I thought that the cap was bad, so I replaced it, along with new cables, Coil (12v), rotor. I bought a new condenser, but have not replaced, as I don't see how that could be causing my issues.

It seems to idle much better than when it is under a load (baling), but it just does not run smoothly...

I also loosened the 2 bolts to holding the distributor, so I could adjust the timing (without a timing light...) I rotated it counter clockwise (if looking from the top of the distributor) and it really ran bad, so I rotated it the other way and it seemed to run smoother, I rotated about 1/2 inch, which seems like a very long distance to me. I was afraid to go any further. This seemed to help the most, but still lagging with power under a load.

Question: can the timing just get off so quickly, and if so, how?

Not sure what else would cause the lack of power, and inconsistent engine running.

Thanks
Tony

Sounds like a fuel delivery problem like dirt in carb,sediment bowl, etc.

That could cause backfiring? Sorry, I was just never very good with carbs...

(quoted from post at 17:07:45 07/02/12)
Question: can the timing just get off so quickly, and if so, how?

Click to expand...

Tony - Yes! This is what can happen if the hub has broken on the cam drive gear. It's not uncommon with this engine with a live hydraulic pump.

A couple quick tests:

- With the engine idling check the timing with a timing light. If the TDC notch on the pulley does not appear steady - ie. it moves randomly around - a busted cam gear is the likely culprit.

- Set the crankshaft at TDC, mark the rotor position on the distributor (should be under #1 or #4 nipple on the cap) then unbolt and slide back the hydraulic pump/distributor assembly. Now reach inside the timing gear case and grab top of the cam gear. If you can move it AT ALL with finger pressure the cam gear has failed.

First thing I'd replace is the condenser. Classic description of condenser failure.

Sounds like fuel is restricted from reaching the carb. Check the screen at sediment bowl, and for a rusted gas tank causing the clog, or plugged vent hole in the gas cap. Set the dist. back to where it was.Yes, Lean mixtures will make it backfire, especially on a cold engine. Also I would file the points a bit and put in new plugs too as long as your at it,might as well, then all your ignition will be up to snuff.

OK. I will take the timing light our with me tonight.

Stupid question. If I am looking at the engine from the Distributor side, I see stamped on the engine, firing sequence, 1-3-4-2. Which is the #1 piston, closest to the tractor seat, or closest to the fan blade? I don't have my owners manual with me at work, and not sure if it tells me anyway.



This does not seem like a fun thing to fix, if it is cam failure, does that mean taking the engine apart?

Just thinking--possible intake manifold gasket failure. Check by squirting engine oil around area of head & manifold juncture.

THanks, Where is the feul filter screen, I thought it was in the tubing the screwed into the Carb, last time I took that off, I didn't seen any little screen, am I looking in the correct place for the screen. If so, seems kinda little for a screen don't you think? would it be better to put in line a bigger plactice see through filter?

I do like the idea that it might be a Carb issue, rather than a Cam issue. Guess I need to check both.

#1 is closest to radiator---front. Put the condenser in first. It is easiest & simple to do.

#1 cylinder is at the front (fan end) of the engine. Run a timing check and report back what you find!

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The good news: Replacing the cam gear is NOT that difficult - you need only remove the timing gear cover to get at it. It does however require removing the front bolster assembly (large and top heavy) which requires loader or engine hoist to safely handle.

An extremely lean condition (restricted fuel flow) can cause backfiring.

Do the easy things first, rough running with no warning is usually a partially plugged outlet from the gas tank. Look inside with a flashlight and run a wire into the outlet. Also the screen you mentioned is in the inlet to the carb AFTER you remove the gas line. As a last resort drain the tank and unscrew the sediment bowl and clean it. You do NOT need a extra filter. The other things mentioned such as timing are not likely, unless you really do have a bad cam gear, which is also unlikely.

You need to remove the gas line at the carburetor
and see if there's a full flow of gas from the tank to the carb. Hold a clean container to catch the gas. If it's just a trickle your tank needs cleaning. If there's a full stream of gas from the tank remove the tube fitting from the carb and look for a screen behind the fitting. If it's clean I would clean the carburetor by soaking in carb cleaner and use air pressure to blow out the jets. If that carburetor has main jet adjustment scr/w you need to open it as this will enrich the fuel mixture. If that carb. has a solenoid that shuts off the gas it may not be opening fully. Hal

Well here is an update.

Since I already had the condenser in hand, I decided to change it out. Well as luck would have it, I drop that little darn screw that holds it in place and can't find the darn thing...adding insult to injury, the tractor is sitting on the edge of my pasture, I had just pulled off the last hay bales and started irrigation on the field. So it will be under about an inch of water when I get there again. I know I know, should have moved the tractor out of the field at least, but I was thinking "how hard is it going to be to change out a simple little capacitor" Start the laughing now....


So after frantically trying to find the screw, I gave up and hoping I could just buy one at HomeDepot or Lowes, since I found out it is a #8-32 x 3/16" I might be lucky in that aspect at least..

Tony

First, pulling the little plug in the manifold is not a valid engine diagnosis test in any book or school of thought. Opening that up makes a good engine run bad and a bad engine run worse.

Second, you probably have the timing significantly retarded at this point. The tractor will idle VERY smoothly with the timing retarded, but it will not have any power, and won't accelerate smoothly.

For all we know you may have already fixed the issue, but with the timing being so retarded, it still lacks power.

There is one "sweet spot" where the timing is just right, and it's nearly impossible to do with a timing light. You have to keep tweaking it until the engine accelerates smoothly and develops maximum power. A keen ear can hear when you hit the sweet spot just listening to the engine run at about 1/2 throttle.

There are only two ways the tractor can jump time:

1. Someone left the distributor loose, and it rotated.
2. Something broke in the cam geartrain. However, if something is broken either the tractor won't run, or you will be chasing a moving target with the timing.

The old AC Gilbert Erector sets used this size screw -

Thanks for all the suggestions.

I will replace the condenser, put the Distributor back together, check/clean the fuel filter and clean the Carb if necessary. If that don't fix it, then it looks like it might be the Cam issue...

I will update when I get back from working on it Tomorrow. Fourth of July fun with fixing a tractor!!



Have a great 4Th of July everyone!!!

Tony

I hope everyone had a Great Fourth of July. and everyone still has all their fingers


Well, I changed out the condenser, and checked the filter on the Carb. The filter had a few grains of sand or something, but didn't look all that bad, cleaned it up and put it all back together.

The tractor fired right up and purred again. Drove it around a little and I didn't notice any lack of power.

Thanks for all the helpful hints to look at for this!!!

One a side note:
I did put the timing light on after the fixes. I still see the notch jump a little bit. By a little bit, I would say it moves about half an inch. Is that normal, or does it still suggest that I have something a little more in depth that needs fixing, like the Cam that was suggested?

Thanks
Tony