any Cat D4 ht4 owner mechanics out there?

Yes the manifold should come off without any other disassembly. As for the throttle the rod that goes to the carb. has a small plate on the rod that goes against the throttle arm and it sounds like it got turned on the wrong side of the throttle shaft arm of the carb. so take another look and you,ll see what I,m talking about as to how it works. Probably all it will need is to get it turned on the right side of the carb. throttle shaft arm (tang or stem) on it.

Yes the manifold should come off without any other disassembly. As for the throttle the rod that goes to the carb. has a small plate on the rod that goes against the throttle arm and it sounds like it got turned on the wrong side of the throttle shaft arm of the carb. so take another look and you,ll see what I,m talking about as to how it works. Probably all it will need is to get it turned on the right side of the carb. throttle shaft arm (tang or stem) on it.

you may also want to make sure that your governor is working properly. you dont want the engine to break on you. on my HT4 before i go to start the pony motor, i usually engage the pinion that drives the diesel engine, and then start the pony motor. this works for me because i dont end up grinding gears when trying to engage it.

thanks, great tip. Do you practice what some say about having the pony run the diesel for a few minutes to bring up oil pressure and heat before throwing on the compression and diesel throttle?

Welcome to the club, I'm new at this club too and these fellows are a wealth of knowledge. On my D2 I run the pony with no compression on the diesel engine until the diesel engine exhaust manifold is warm to the touch. I learned this from an old cat owner neighbor of mine. not sure if this is the correct procedure but any of these fellows can set us both straight.

have fun with your kitty!!

Dennie G

When the starting engine is turning the diesel good then flip the compression release to run position and more heat will build up quicker from compression than in the released position.

Good To Know!!
Thanks

If the throttle rod is just hanging there, look for the small bracket that the far end of it slides in.

The tab that's welded on the rod should pull the throttle linkage between the governor arm and carburetor toward the left side of the machine when the knob is pulled out. The governor will try to pull it back to the right side if the pony engine is running slower than about 3500 rpm.

So your pony throttle control should pull out to restrain the governor arm and slow it down to idle for starting and pinion engagement, then push it in to give the governor some room to speed it up a bit before engaging the pinion clutch. Push it all the way in once you get the main engine turning (compression lever to start or out position depending on the age of your machine) and the governor will usually overshoot a bit and then quieten down and control the rpm properly. Flip the compression on (run or in position) and the pony motor should really go to work as the governor opens the throttle in response to the increased load.

Once you get it warmed up, open the diesel throttle quite a bit. It should have already had oil pressure built up, so there's no reason not to let the diesel have enough fuel to run at least half speed. I know some like to barely crack the diesel throttle on, but in my book, that's just a way for it to pop a few times and kick the pinion latches out and then die. I want it to pop on one cylinder and catch on the next one and the one after that and never stop until I shut it off.

If it won't hit or only kicks out the pinion latches, close the diesel throttle again, release the compression, re-engage the pinion and pinion clutch, apply the compression and warm it some more before trying the diesel again. You do not want to keep putting diesel into the cylinders when it's too cold to start. This washes the oil film off the cylinder walls and causes increased wear/scuffing.

Starting anything with a pony, I go through something like this; Start pony and let it warm until it runs w/o choke. Engage the pinion, open throttle on pony and start spinning main engine with compression off until oil pressure builds plus a few minutes (depending on outside temps). Then engage compression on the main and let 'er spin until the middle of the main's head reaches body temp. Open throttle on main to about 1/3 and let 'er rip. As soon as the main is running and kicks the pony out, close fuel valve on pony and let it run out of gas. The reason for shutting the gas off rather than just switching the engine off is that when the main is running, vibration can make the needle valve in the carb leak and let gas get by and into the pony's cylinders. .and into the crankcase.