550 gas adventure

[kenbob]

I have had my 550 a month or so and still trying to figure everything out. It does not want to go over 1700 rpm and it does not run as smooth as most. I have: new plugs, new wires, valve adjustment, carb kit. It idles nice, it seems to run worse the warmer it gets.

The tractor set for 2 years. From the color of the oil and the cleanliness of the head it would seem it at least had a valve job before it quit being used.

I have not yet, done the timing and have not yet replaced the power valve on the carb. It is a type C marvel with that adjuster in the bottom and does not come with any carb kits I have found. Have not done a compression check.

I noticed a few things while taking it apart. The down draft tube has something that looks like a check valve. Tractor is a 64" is this some sort of PCv (picture enclosed). Tractor has electronic igniton. I have enclosed a picture of the ballast resistor. The post at the top end is a bit loose? is this the issue?

Also the alternator has a 2 spade connector on the side. Does this mean i could get an electric tach for it?

 

[Jim.ME]

I have had my 550 a month or so and still trying to figure everything out. It does not want to go over 1700 rpm and it does not run as smooth as most. I have: new plugs, new wires, valve adjustment, carb kit. It idles nice, it seems to run worse the warmer it gets.

The tractor set for 2 years. From the color of the oil and the cleanliness of the head it would seem it at least had a valve job before it quit being used.

I have not yet, done the timing and have not yet replaced the power valve on the carb. It is a type C marvel with that adjuster in the bottom and does not come with any carb kits I have found. Have not done a compression check.

I noticed a few things while taking it apart. The down draft tube has something that looks like a check valve. Tractor is a 64" is this some sort of PCv (picture enclosed). Tractor has electronic igniton. I have enclosed a picture of the ballast resistor. The post at the top end is a bit loose? is this the issue?

Also the alternator has a 2 spade connector on the side. Does this mean i could get an electric tach for it?

If it is charging as is, it is most likely a one wire Delco type that has lost the rubber plug that should be over the two spades. Those terminals are not where a tach can connect.

 

[kenbob]

Thanks for the quick reply! I guess I will replace the power needle in the carb and the ballast resistor.

 

[rrlund]

I seriously don't think you need a blast resistor with electronic ignition. Take it off. If that's a 64, the alternator wouldn't have been stock. I don't think they switched to alternators until 65 or 66.

 

[Jim.ME]

Is the adjusting needle damaged? I wouldn't worry about replacing it, just shine the tip up with some real fine emery or crocus cloth, it screws in and out to adjust, personal opinion I don't see a new needle changing that circuit appreciably.

 

[kenbob]

So when I unscrew the jet from the bottom I have somthing like this. No needle as such

 

[Jim.ME]

I believe if you turn the L handle in, the needle should protrude to engage the actual jet which is inside the carb. You should see it when you look in the hole you took the adjustment of. The jet has a specific size hole in it. Adjusting the L handle moves the tapered end of the needle in and out of the jet opening to adjust fuel flow under load.

Do you have a copy of the Marvel Schebler TSX service manual?

 

[kenbob]

I believe if you turn the L handle in, the needle should protrude to engage the actual jet which is inside the carb. You should see it when you look in the hole you took the adjustment of. The jet has a specific size hole in it. Adjusting the L handle moves the tapered end of the needle in and out of the jet opening to adjust fuel flow under load.

Do you have a copy of the Marvel Schebler TSX service manual?

No only instructions from the carb rebuild kit, that didn't have the valve. Mine actually is the same thing but with a round dial. if I have to get new, i will need that one as not enough room for the L. I probably will take the carb off again and see if it isn't seated correctly

 

[Jim.ME]

Here is a link to a Marvel Schebler manual for the DLTX and TSX carbs that may help you.

Marvel Schebler DLTX and TSX Manual

I misspoke about the adjuster needle seating in the jet opening, the picture below better explains it. I outlined the jet in green, the adjuster is outlined in red. The jet is sized for the maximum fuel flow. The adjuster needle seats inside it as the cutaway shows. that allows tailoring the fuel flow to the jet for performance under load. If you look on the jet end of the adjuster, you should be able to see the end of the adjuster needle (L or Knob type) move into or out of the seat inside the adjuster body.

 

[used red MN]

I seriously don't think you need a blast resistor with electronic ignition. Take it off.

This bares a little more investigation before removal of the ballast resistor. If the previous owner installed a 6 volt coil then it would need to be retained. A 6 volt coil would have 1+ to 2 ohms of resistance across the primary terminals (small terminal posts). I would hate to see you burn out your EI module. I’m not sure if Olivers used the bypass circuit for 12 volts to the coil during cranking from the “I” terminal on the starter solenoid? This setup requires a 6 volt coil and a ballast resistor.

 

[kenbob]

The ohm reading is 1.4. The solenoid is only 2 large, 1 small post if that tells us anything.

 

[Jim.ME]

The ohm reading is 1.4. The solenoid is only 2 large, 1 small post if that tells us anything.

solenoid would need a second small terminal to have a ballast resistor bypass for starting.

 

[kenbob]

solenoid would need a second small terminal to have a ballast resistor bypass for starting.

It took some looking to find the load nozzle and screw, but finally found it. THen found a kit that had it for less money than the 2 parts seperately. I couldn't find that when I ordered the kit the first time.

 

[Jpvano28]

Hey Ken, I had a similar problem a little while back. The load adjustment pin with the "L" isn't great. Get the other one, it looks like a "T" instead. With that said, Check the float and make sure it's sitting right inside the carb, it needs to sit level with about a 1/2 of an inch clearance. Then while it's running, loosen up the distributor nuts and slowly turn it counter clockwise or clockwise to advance the timing or retard it. You'll hear the difference. if it sounds like it going to stall, go back the way you came. Until it sounds right. Also I noticed the fresh air tube housing has something in it, I'm pretty sure that's supposed to be clear of any obstruction's. Also, tighten up the bell housing on the throttle arm a little bit, sometimes its not fully engaging the governor if it's loose. I hope this helps you moving forward.

 

[kenbob]

Thanks JP. a Shop manual isn't always much help when a tractor is 60 years old and has been rigged in many different ways. Have a compete kit with load adjustment on the way. I will work on all your suggestions and if still not right, order a Flamethower II coil, and then I won't have to worry about a resistor or no resistor. The air tube housing: What you are mentioning is not the down draft hole but a hole next to it with some sort of valve in it. It is a 1964. Did they put some sort of polution control valve on it. The tube itself is clear. Cant figure out with the gaget is.

 

[Jpvano28]

Thanks JP. a Shop manual isn't always much help when a tractor is 60 years old and has been rigged in many different ways. Have a compete kit with load adjustment on the way. I will work on all your suggestions and if still not right, order a Flamethower II coil, and then I won't have to worry about a resistor or no resistor. The air tube housing: What you are mentioning is not the down draft hole but a hole next to it with some sort of valve in it. It is a 1964. Did they put some sort of polution control valve on it. The tube itself is clear. Cant figure out with the gaget is.

That's a good question, I have no idea what that could be, on mine (59) the housing is hollow as the tube is also. As far as getting it dialed in, these old girls are finicky lol .. So just take your time, you'll get it. Remember, it's supposed to be a fun and relaxing project. Sometimes.. Glad I could help you along Ken..

 

[kenbob]

I have the operators manual but haven't orderd shop or parts manual yet. I want to make sure I get one new enough to cover the parts on my tractor. Made that mistake with another tractor. It wasn't current with the tractor I had.