Engine questions, need advice

[ancomcabs]

Older 630 with VH4D engine. Have not used it much other than some short periods of snow plowing this winter, Don't really know the history of the machine. What I do know is engine is easy starting, even in the cold since I adjusted the choke. All fluids are fresh. New cap, rotor, and wires, has electronic ignition. New plugs, replaced rectifier and regulator. Fuel delivery seem good and it looks like the inline filter was changed recently Was running it for about an hour today, moving some dirt around, started to bog down, stopping and fooling a little with the choke would keep it going but only for a little bit then I'd have to do it again until finally it just stalled. I let it sit a while and got it going again to put it on the trailer but did not work it. I'm thinking it has something to do with the carb since I did adjust the choke a while back. I adjusted the choke because I was having a very hard time starting it in cooler weather, after I adjusted it would start when very cold so I thought everything was good Just looking for some advice or direction on where to look? carb or something else? Thanks in advance

 

[jerry]

How warm was the weather when this happened? Had a 610 with same motor and it had a overheat sensor on one cylinder head . On warm days if I worked it hard it would occasionly shut down till it cooled somewhat. It was a small button thermo with one wire running from ignition coil to it.

 

[ancomcabs]

How warm was the weather when this happened? Had a 610 with same motor and it had a overheat sensor on one cylinder head . On warm days if I worked it hard it would occasionly shut down till it cooled somewhat. It was a small button thermo with one wire running from ignition coil to it.

It was today in New England, about 50 degrees this afternoon. I was thinking about engine temp but that's hard to tell, no radiator to check and the engine light ( which appears to be working) does not come on. I've also taken most of the covers off and cleaned the cooling fins when I first got it. Where would I look for this sensor? Or do you think the repair manual would show it having one?

 

[OldMachinist]

It was today in New England, about 50 degrees this afternoon. I was thinking about engine temp but that's hard to tell, no radiator to check and the engine light ( which appears to be working) does not come on. I've also taken most of the covers off and cleaned the cooling fins when I first got it. Where would I look for this sensor? Or do you think the repair manual would show it having one?

Sounds like either a sticky float or needle in the carb or maybe a little crud in the carb worked loose clogging a jet.

 

[ancomcabs]

Sounds like either a sticky float or needle in the carb or maybe a little crud in the carb worked loose clogging a jet.

Ordered a carb rebuild kit, never did one, anything to look out for? Thanks

 

[OldMachinist]

Ordered a carb rebuild kit, never did one, anything to look out for? Thanks

When I take a carb apart I work in a tray to catch any small parts that might fall out and roll away to never be found again.
Take pictures of how the linkage hooks up.
Clean the exterior before dis-assembly
Count the number of turns the adjustment screws are turned out before disassembly
Take more pictures as you disassemble
Soak disassembled carb in cleaner at least overnight
Never use anything steel to clean out jets. Use small copper or brass wire.
Reassemble and set adjustment screws where they were.
Fine tune adjusment after engine warms up.

 

[Tigerhaze]

Sounds like either a sticky float or needle in the carb or maybe a little crud in the carb worked loose clogging a jet.

I have the same issue with my 630- mine was due to a sticky float in the carb as mentioned. Using the rebuild kit is the permanent solution, but in the meantime if you need to use the machine I have found that gently rapping the carb bowl with a small hammer can knock the float loose and get you back to working for a while. This also works on other machines usch as 8N tractors (another one of my machines that had a similar problem).

 

[ancomcabs]

I have the same issue with my 630- mine was due to a sticky float in the carb as mentioned. Using the rebuild kit is the permanent solution, but in the meantime if you need to use the machine I have found that gently rapping the carb bowl with a small hammer can knock the float loose and get you back to working for a while. This also works on other machines usch as 8N tractors (another one of my machines that had a similar problem).

@Old M- Thanks for the advice @Tigerhaze- I hope that's all it is and you are right!

 

[ancomcabs]

@Old M- Thanks for the advice @Tigerhaze- I hope that's all it is and you are right!

Tried some work again today. Carb kit did not come yet but used some carb cleaner, made no diference. Same results today only did not run as long before the trouble started. Tapping the carb fuel bowl made no difference. Had to wait a while to get it going again which makes me think it is heat related. Also let it sit a couple hours once I got it back on the trailer and it fired right up. Not sure what to do next, I've cleaned all the fins and blown them out good. It was warm here today, about mid 70's, but I barley got 30 minutes out of it before the trouble started. So if the engine is overheating what can we look at as a cause on an air cooled engine? Could the 35 year old VH4D just gotten too tired to work anymore? Hoping someone here with more knowledge than me can send me in the right direction

 

[OldMachinist]

Tried some work again today. Carb kit did not come yet but used some carb cleaner, made no diference. Same results today only did not run as long before the trouble started. Tapping the carb fuel bowl made no difference. Had to wait a while to get it going again which makes me think it is heat related. Also let it sit a couple hours once I got it back on the trailer and it fired right up. Not sure what to do next, I've cleaned all the fins and blown them out good. It was warm here today, about mid 70's, but I barley got 30 minutes out of it before the trouble started. So if the engine is overheating what can we look at as a cause on an air cooled engine? Could the 35 year old VH4D just gotten too tired to work anymore? Hoping someone here with more knowledge than me can send me in the right direction

How old is the ignition coil? It could be going bad and shorts out when it gets hot.

 

[ancomcabs]

How old is the ignition coil? It could be going bad and shorts out when it gets hot.

I've been googleing this since my last post and that is one of the solutions I've read about. Is there any way to test the coil or is it just cheap enough to replace?
I've also seen suggestions from stick valves to vapor lock. For the sticky valves it was suggested to put a couple of squirts of auto trans fluid into the carb. For the vaporlock/over heat thing it was suggested to make a cut in the manifold to separaate the intake and exhaust side as well as a sheet metal plate under the carb to act as a heat shield, any of these things sound like a solution?

 

[OldMachinist]

I've been googleing this since my last post and that is one of the solutions I've read about. Is there any way to test the coil or is it just cheap enough to replace?
I've also seen suggestions from stick valves to vapor lock. For the sticky valves it was suggested to put a couple of squirts of auto trans fluid into the carb. For the vaporlock/over heat thing it was suggested to make a cut in the manifold to separaate the intake and exhaust side as well as a sheet metal plate under the carb to act as a heat shield, any of these things sound like a solution?

Coils that work intermittantly can be hard to test. A standard 12 volt coil is cheap. Borg Warner part #E502 if the auto parts place need a number to cross reference.
Vapor lock is easy to test for. Just give it a squirt of fuel or starting fluid in the carb right after it quits. If it fires up or tries to then its not getting any fuel.
There's procedure in the Wisconsin service manual for cutting the manifolds apart for engines that vapor lock often. If you need it let know and I'll try to find it.

 

[ancomcabs]

Coils that work intermittantly can be hard to test. A standard 12 volt coil is cheap. Borg Warner part #E502 if the auto parts place need a number to cross reference.
Vapor lock is easy to test for. Just give it a squirt of fuel or starting fluid in the carb right after it quits. If it fires up or tries to then its not getting any fuel.
There's procedure in the Wisconsin service manual for cutting the manifolds apart for engines that vapor lock often. If you need it let know and I'll try to find it.

I've know I've seen something online before but can't seem to locate it now. If you can find it without too much effort that would be great- Thanks

 

[OldMachinist]

I've know I've seen something online before but can't seem to locate it now. If you can find it without too much effort that would be great- Thanks

 

[ancomcabs]

Thanks OM, if I interpret this correctly I should not cut completely thru? just reduce the width of the connection?

 

[OldMachinist]

Thanks OM, if I interpret this correctly I should not cut completely thru? just reduce the width of the connection?

That's the way I read it too.

 

[ancomcabs]

That's the way I read it too.

Update Installed new fuel filter and moved it outside the engine compartment, routed fuel line as far away from the engine as possible. managed to install an aluminum shield between the carb and exhaust manifold on one side to help keep heat away. My manifold did not look exactly like the picture, I did cut a little away but I was reluctant to cut too much, don't think what I did made much of an affect. Started her up and let it idle/get hot for about 20-30 minutes then got in and started moving around, not lifting material or anything, lasted about 3 minutes then it stared to die! Not sure what to try next, I did check the temp in several places with an infared when it was running the exhaust manifolds were up around 400 degrees, the carb itself was much lower ~135-150. the fins on the heads were lower as well ~200-220. the fuel line was below 100 as well. Any ideas?

 

[OldMachinist]

Update Installed new fuel filter and moved it outside the engine compartment, routed fuel line as far away from the engine as possible. managed to install an aluminum shield between the carb and exhaust manifold on one side to help keep heat away. My manifold did not look exactly like the picture, I did cut a little away but I was reluctant to cut too much, don't think what I did made much of an affect. Started her up and let it idle/get hot for about 20-30 minutes then got in and started moving around, not lifting material or anything, lasted about 3 minutes then it stared to die! Not sure what to try next, I did check the temp in several places with an infared when it was running the exhaust manifolds were up around 400 degrees, the carb itself was much lower ~135-150. the fins on the heads were lower as well ~200-220. the fuel line was below 100 as well. Any ideas?

Did you replace the ignition coil?

 

[ancomcabs]

Did you replace the ignition coil?

The coil was replaced a couple months ago when it was still cold out. It was from the local auto parts store so I guess it could potentially be the wrong one?