DC4 governor

[oldproudvet]

Gentlemen - When I brought me DC home a while ago it did not have a gen belt and ran just fine. Had it in the shop this winter and one to things addressed was the belt, seeing as how I wanted an operating generator. When the engine is started the gov arm hits the belt and does not allow the carb to throttle back, it's about half way open. Idle adj screw can't possibly do it's job and the engine is almost running away........ Any thoughts? I disconnected the gov arm from the carb so the throttle could close and it runs as normal. Thanks - Larry

 

[chuck machinist]

You must relocate the generator bracket to align the gen pulley The generator belt is hitting the governor arm as you stated. If I remember correctly. I moved the generator forward to create a gap, which just cleared the arm, keeping the fan pulley and gen pulley aligned. CM

 

[mEl]

The first thing I would do is check the setting of the throttle arm, Engine shut off , with the carb disconnected, the throttle wide open and the carb throttle arm held in wide open position the rod should just fit through the carb arm hole. Are the pullies out of alignment ? On some I have had to put a bend in the governor rod to get proper hookup.
My 39, when the throttle is in W/O position the throttle arm where it connects to the carb rod is near flush with the front of the block. Can you take pictures and post them so we can see.

 

[John Saeli]

The first thing I would do is check the setting of the throttle arm, Engine shut off , with the carb disconnected, the throttle wide open and the carb throttle arm held in wide open position the rod should just fit through the carb arm hole. Are the pullies out of alignment ? On some I have had to put a bend in the governor rod to get proper hookup.
My 39, when the throttle is in W/O position the throttle arm where it connects to the carb rod is near flush with the front of the block. Can you take pictures and post them so we can see.

RE: The Pics: What The ???????????????????????????????????????????????????????????????????????????????????????????

 

[J Hamilton]

The first thing I would do is check the setting of the throttle arm, Engine shut off , with the carb disconnected, the throttle wide open and the carb throttle arm held in wide open position the rod should just fit through the carb arm hole. Are the pullies out of alignment ? On some I have had to put a bend in the governor rod to get proper hookup.
My 39, when the throttle is in W/O position the throttle arm where it connects to the carb rod is near flush with the front of the block. Can you take pictures and post them so we can see.

Ummm. That's an interesting setup

 

[Mike Fitz]

Electric fan and water pump? relocated alternator, what a neat bit of engineering!

 

[mEl]

Thank you Mike, my purpose was to show the arm movement but for some reason my email system does not want me to send videos, I will be sending stills to show actual arm position and travel which is probably less than two inches, compare pics. this is my 39 puller, I will send more tractor pics when I get it out of the shop for anyone who cares to see them. Pic 1 is at idle, Pic2 is at w/o throttle. I am running a Marvel Schebler TSX series carb but that makes no difference as the arm position on the carb is the same. The early two bolt 4-7-800 and early 830s MS carbs have the two bolt air cleaner hookup and fit perfectly in place of the Zenith, and in my opinion a nice upgrade.

 

[mEl]

RE: The Pics: What The ???????????????????????????????????????????????????????????????????????????????????????????

Hey John, a good computer store may be able to fix that sticky key for you.

 

[Mike Fitz]

What do you like about the carb upgrade?

 

[oldproudvet]

RE: The Pics: What The ???????????????????????????????????????????????????????????????????????????????????????????

John when you hold the arm wide open it hits the fan belt

 

[oldproudvet]

Gentlemen - When I brought me DC home a while ago it did not have a gen belt and ran just fine. Had it in the shop this winter and one to things addressed was the belt, seeing as how I wanted an operating generator. When the engine is started the gov arm hits the belt and does not allow the carb to throttle back, it's about half way open. Idle adj screw can't possibly do it's job and the engine is almost running away........ Any thoughts? I disconnected the gov arm from the carb so the throttle could close and it runs as normal. Thanks - Larry

Thanks guys for all the thoughts. The problem is fixed. I took the rod from the gov arm to the carb and shortened it 1/2". That pulled the arm back far enough and it does not hit the belt and the pulleys are nicely aligned. I had to swivel off and tap half an inch of more threads, then cut the rod off by 1/2". Simple fix once I understood what was going on. Thanks again - Larry

 

[mEl]

OPV, Your governor will be much more responsive if you adjusted the rod length as I described, I knew when I read your Post that the governor arm to carb rod length was off. When the throttle is pulled wide open the flyweights in the governor housing are collapsed inward under governor spring action when it is held into W/O throttle and the rod length should be an exact fit into the carb lever when the carb lever is held in the w/o position, If done properly the arm will be nowhere near the belt, Now getting clearance for the arm and throttle when you install an alternator, that's another issue with a stock Gen belt.

 

[mEl]

What do you like about the carb upgrade?

Mike, in my opinion the MS is a simpler carb and I use them on all the puller engines I build, DCs and other models as well. I can tailor a MS for the engine CID I am building. I can build my own venturii to the size that best fits the engine flow characteristics that I am building out of 1.5" aluminum bar stock on a small 6" lathe, the Idle circuit on an MS is very responsive and smooth. I also do Carb body and jetting mods to increase fuel flow. A properly set up Marvel can be idled down till you can hear every cylinder fire. I have made straight wall venturii at near 1.300". A stock big 400 is around 1.0" maybe a bit smaller, A 830 is 1,060 and my choice for a 4.0625 DC. The biggest issue with the Zenith is the fact that it has a compound Venturi which makes mods to airflow characteristics nearly impossible. Try to keep in mind I am building primarily special use carbs and factory carbs are sized to ag RPM specs. I make changes such as cams and ported heads with larger valves and out of the engines normal RPM range so carb mods are the norm.

 

[J Hamilton]

Mike, in my opinion the MS is a simpler carb and I use them on all the puller engines I build, DCs and other models as well. I can tailor a MS for the engine CID I am building. I can build my own venturii to the size that best fits the engine flow characteristics that I am building out of 1.5" aluminum bar stock on a small 6" lathe, the Idle circuit on an MS is very responsive and smooth. I also do Carb body and jetting mods to increase fuel flow. A properly set up Marvel can be idled down till you can hear every cylinder fire. I have made straight wall venturii at near 1.300". A stock big 400 is around 1.0" maybe a bit smaller, A 830 is 1,060 and my choice for a 4.0625 DC. The biggest issue with the Zenith is the fact that it has a compound Venturi which makes mods to airflow characteristics nearly impossible. Try to keep in mind I am building primarily special use carbs and factory carbs are sized to ag RPM specs. I make changes such as cams and ported heads with larger valves and out of the engines normal RPM range so carb mods are the norm.

Hey mEl, have you had those engines you've built on a Dyno? Just curious what kind of HP you're getting with all those mods.

 

[mEl]

J, When just assembled with no break in time on a M&W dyno it was 55 hp at 1100 ---65 at 1400 and 75 at 1800 RPM, these are calibrated check points, our dyno has checked out well on other tractors of known advertised hp. I just completed the mods show in the pics and the gains from them have not been tested but definitely it is snappier according to my driver. Our Dyno is at one of our other stores presently and right now I have no access to it. I am as curious as everyone else! Here is a pic of my 4 5/8 build with fire rings and no head gasket, it was 125 HP with no break in time. It works well!