HELP Massey 165

I have this posted in the Massey Ferguson group but I figured I needed to get it out there for as many people to see because I need the brain power! It's a 1971 massey 165 with the 4 cyl perkins gas engine.
It seems like it has been nonstop with this tractor. Ive had a lot of issues but for the past couple months the tractor has ran the best it ever has since I got it. I thought I finally had everything squared away. Then out of nowhere a couple weeks ago the tractor died on me while grading and I haven't been able to get it to run since. It will try to start an occasion only spit and sputter and run extremely rough until it dies. That's all I can get it to do. I have done everything I know to do so I need new ideas or something. I have had the carb apart at least 5 times and have checked and double checked the float level. I've cleaned the carb and put a new seat and needle in etc. The carb was brand new as of earlier this year anyway and and I am definitely getting fuel. As far as my Ignition system goes, it has a new coil, wires,points, condenser, and plugs. I've triple checked the plug gap and cleaned them. I've double checked the new coil. I've checked spark at every plug and have a good blue spark. I've checked the compression on each cylinder and have normal consistent compression. I've checked the timing on the distributor it appears that it is timed close enough to get it running at least. Points are gapped properly on distributor I have even replaced the cap and rotor. Everything on the ignition system seems to be functioning perfect. I have fuel and I have spark, which leaves me with air. My next thought was well maybe I have an intake valve not opening or something along that line to where it won't pull vacuum. I removed the valve cover earlier this evening and cranked it over and watched all the valves operate. there are no valves stuck open or closed. And there is nothing obviously wrong at least. What am I missing? What do I look at next? Someone help please!

I see on some models with that engine they were equipped with an electric fuel shut off solenoid on the carb. Does yours have one? If so does it get power with the key on does it click when disconnected and reconnected with the key on? How about when the starter is cranking the engine? Did you try running a jumper wire from the battery direct to the coil hot lead? You cleaned the spark plugs but what do they look like now after you have tried starting it? If they are rich fouled, black and sooty they need cleaned again or they will not fire properly. Use carb cleaner, wire brush and compressed air. Sounds like you have it close on timing or I do not think it would run even the little bit you described. Connect a test light to ground and hold the probe to the distributor terminal. With the key on does it light when the points are open and go out when they are closed? Does gas flow well OUT OF THE CARB BOWL DRAIN PLUG? Is the venturi in your carb? See 34 in the attached diagram. You have the valve cover off you should set the valve clearance.
AGCO MF 165 online parts catalog

here is about the same problem I had with my Allis Chalmers Model M, gas tractor. It was running fine then it started running very bad. I installed a different. I changed the magneto. Still ran bad. I was disking in tall dry mustard plants. The seeds from the plants plugged the intake air filter so bad it would hardly run. I installed a different air intake filter assembly from another tractor. After that the tractor ran fine. May not be your problem. just another thing to check. If it were mine, I would change the condenser, even though it's new it still may have a problem. From my experience a bad condenser will act like a fuel problem. Another thing is: check the distributor cap for arcing inside the cap. Stan

37 chief has some very good points to check.

We had one tractor with such an issue. It turned out the wire to the distributor was broke inside the insulation. A good tug on the wire showed the break. Another tractor I worked on for a guy had a loose connection at the ammeter and poor connection to the coil.

If it's air then pulling the intake boot off the carburetor and letting it breathe unfiltered air will prove that instantly. Letting it run without the air cleaner for a few minutes won't hurt it unless you do it in the middle of a sandstorm.

Get a can of starting fluid. Give it a spray. See if it fires. It won't "get addicted." That's baloney. Starting fluid is fuel. If it runs with starting fluid it's not getting fuel.

Just out of curiosity how old old is the gas? I have an mta I fought something fierce and in the end it was bad gas and ran fine after draining the tank and putting some good stiff in. But that probably isnt it since it was working then just stopped. However mine wouldn't hardly start and if it did ran rougher than a cob for a few seconds and died.

Be nice to get some feed back to see if any suggestions here have been helpful.

Sorry haven't had time to do anymore looking yet been sick, gonna try tomorrow. The fuel is new and 93 octane so I don't think that's the issue, since it was alresdy running just fine then stopped. I checked all connections and wiring all looks good. I did do starting fluid into the carb and didn't notice a difference so I think I can rule lack of fuel and air out. What really gets me to is that I pulled every plug, one at a time, and watched the spark on each one. Strong blue on every plug. Tomorrow I was gonna try to swap the condenser and clean the points again but I wouldn't think I would have good spark if they were bad?? I'm also gonna check the valve clearances as stated.

Mine does not have the fuel shut off solenoid. And yes venturi is in carb and fuel flows good out of bowl. I'll have to get a test light I guess. Also, something odd I have noticed occasionally, If I drain the fuel out of the sediment bowl And then reopen it fuel does not want to flow freely. It's not the gas cap I've tried it without the cap. I don't remember fuel having not always flown freely even with the bowl empty. Now if I pull the drain plug on the carb then it will start flowing fine. And maybe that is normal but I never noticed that before. It's like that air is creating a vacuum or something. I don't recall ever having to bleed the air out of the sediment bowl to get it to flow

Sounds like it is working right. If a sediment bowl is sealed tight, as it should be, and the carb bowl is full, with the needle seated as it should be, gas will not run into the sediment bowl as the passage for the air in the bowl to get out is blocked. The bowl may slowly fill with gas if the air in the bowl works back up into the tank and out. Pulling the drain plug from the carb bowl, drops the float and opens the needle allowing the air, then gas to flow through the sediment bowl to the carb bowl.

This post was edited by Jim.ME on 11/12/2023 at 05:32 am.

(quoted from post at 01:25:34 11/12/23) Mine does not have the fuel shut off solenoid. And yes venturi is in carb and fuel flows good out of bowl. I'll have to get a test light I guess. Also, something odd I have noticed occasionally, If I drain the fuel out of the sediment bowl And then reopen it fuel does not want to flow freely. It's not the gas cap I've tried it without the cap. I don't remember fuel having not always flown freely even with the bowl empty. Now if I pull the drain plug on the carb then it will start flowing fine. And maybe that is normal but I never noticed that before. It's like that air is creating a vacuum or something. I don't recall ever having to bleed the air out of the sediment bowl to get it to flow

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A bad condenser will point you in any direction except to the condenser.

Then, when you finally change the condenser and it runs normally, you will never forget it.

And yes, your fuel flow scenario is normal.

Alright I wanted to give an update, I've been messing with it for most of the day. Since I had the valve cover off I went ahead and checked valve clearances. I only did a slight adjustment on cylinder one but I don't think it really made much difference. I also rechecked top dead center with the valve cover off And I was quite a bit off on the timing somehow.. in between an 1/8 and 1/4 turn. I put everything back together rechecked spark plug wires, cleaned the points again, and swapped out the condenser with the old one I had. Few small tweaks on idle screw and it's sounding good again.. fired up and running! I appreciate all the ideas and suggestions! So in the end I'm not really sure what the main issue was.. The timing was definitely off but I don't know how it could move that much while driving the tractor. And I would think if it was slipping it would slowly start running crapier and crapier until it wouldn't run at all, not just all of the sudden stop. Maybe it was the condenser as well. I have no way to test them to see if they both are good but I may go ahead and get another spare on hand. I'm just so relieved it's running again hopefully it stays that way!

Glad you are up and running again. Isn't it amazing how good they run when everything works. Stan