The carb does not need a return line attached for the engine to run at idle or high speed.
72 Nordic Tillotson carb
So I'm trying to tune this HR 12A and just running it off a bottle. {not really running yet} My question is ... does this carb need the return line attached, and fuel in the tank to actually idle. It still seems to need a lot of choke to stay running. I just put a new check valve in .....no luck yet! Please help...
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Thats what I thought. Do you have any thoughts on why it needs 95% choke to stay running?
Because it's old and it sounds like it needs to be rebuilt correct .Welch plugs removed and cleaned passages ?Thats what I thought. Do you have any thoughts on why it needs 95% choke to stay running?
Id be checking the fulcrum lever and pop off. Did you use Tilly parts for rebuild or aftermarket?
I rebuilt it w/ Tillotson parts from EC carb. cleaned and replaced welch plugs. fulcrum looked level. I have not tried the pop off tester. I'm new to rebuilding vintage sleds. Maybe I should order a Pop off tester. Do you think Factory setting for the high and low jets are the best place to start. I think the sled had a different carb and someone may have stuck me w/ this HR12A....
Ok, the HR carbs may not need a return line, but if it is working properly the pump should be drawing gas into the carb and it will be pissing out the return nipple...
Thanks for the info. i'll be sure to check and see if the return is getting gas. I think it's dry. {i thought it was for air}
When you say run off a bottle, do you mean a squirt bottle or do you have the gas line in the bottle? Are you sure it's sucking gas/pump is working? Have you confirmed the order of the diaphragms/gaskets with your rebuild?
Your pulse should run through your intake. Little hole. Make sure the intake gasket is orientated correctly to allow the pulse. It sounds like she isn't getting enough fuel if nothing is coming out of the return.
Your pulse should run through your intake. Little hole. Make sure the intake gasket is orientated correctly to allow the pulse. It sounds like she isn't getting enough fuel if nothing is coming out of the return.
Are you sure the carb is a 12A ? The correct carb for a 72 Nordic 440 is a HR112A, may be you have the correct carb.So I'm trying to tune this HR 12A and just running it off a bottle.
After a deeper dive... this is a HR 12 A for sure. So the pulse holes all line up but this carb has a ... looks like brass plug in the pulse hole. Drill it out? that idea of mine, my really not loving .
that idea of mine, my really not loving .Thanks BB9076 I need to mention that I had a gas line in a bottle of fresh pre mix. Going though the rebuild one more time, just to make sure all is correct.
I doo not think a HR 12A was ever used on a Ski-Doo. So guessing a bit here. If it has a brass plug in the pulse port it is/was set up on a external pulse application. So where is the fitting located on the 12A carb that you are calling a return line fitting ?? Is it on the side of the carb body or in one of the stack plates ?? I dont know that carb but with a low ID number I would be surprised if it has a return line.
Dont drill out the brass plug yet.
Dont drill out the brass plug yet.
The return line is in the top stack near engine intake. I wish my computer would let me download a few pics
According to page 4 the HR12A is for an Arctic Cat or Scorpion:
Just checking, if this is for a '72 Nordic 440e, the engine should be a Rotax Type 434E (should be a tag on the right side of the engine I think, around the fan housing).
And the snowmobile build date will be 1971 (as stamped in the tag on the tunnel).
And the snowmobile build date will be 1971 (as stamped in the tag on the tunnel).
You are correct. The tunnel tag has 1971
Doo I need to find a different carb or might this model work . Other than I have no good way to hook up the choke cable.
Just checking, if this is for a '72 Nordic 440e, the engine should be a Rotax Type 434E (should be a tag on the right side of the engine I think, around the fan housing).
And the snowmobile build date will be 1971 (as stamped in the tag on the tunnel).
Found it. TYPE 435
Hmm, Type 435 is from a '72 or '73 T'NT (+maybe others?) Looks like the original Nordic engine was swapped at some point. Maybe worth looking up how the T'nT carb was set up.
Lots of info at vintagesnow
Lots of info at vintagesnow
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