Carburator issues

[ryant]

I am putting a 72 Trail Boss back together and do not know where to hook up the 2 gas lines at. There is a quarter inch nipple on the engine block not sure where that goes.
The carb has 2 fittings. 1 on the bottom by the diaphram or fuel pump and 1 near the middle/top?
So far it does not want to stay running on its own. Model HR16B Tillotson carb

[arp35]

I am no expert but the engine should have some sort of fuel pump (either mechanical or pulse) however I guess it could also be a gravity feed. The nipple on the engine block could be the intake to a mechanical fuel pump but there should be an outlet that would then connect through a fuel line to the top or side of the carb. The bottom connection may be a drain for the bowl. Did you try googling the engine type or carb to see if there are any manuals on line?

Try this link:
000webhost.com - free web hosting provider
I could not check it at work (internet nazi's denied access). I found it here:
Engine/Carb Data at he bottom of the page are more links. It looks like it is used on a 400cc Rotax snowmobile engine. Hope this helps.

[greggv2007]

The nipple on the bottom is the fuel inlet, the one on the engine block is the pulse line for the fuel pump and it will connect to the nipple near the top of the carb.

[hon450r]

i am having the same problem with my carb setup. i have the tilly hr38a carb. has a tiny nipple on the intake flange of the carb. a pulse type nipple on the top center of the carb. the plastic fuel inlet on the bottom and another nipple on the bottom as well. from the research i dug up the top goes to block. the plastic bottom one is the fuel inlet. and the other nipple on the bottom of mine is a return. correct me if i am wrong please but that is what i read on the hr but i can not for the life of me find any info on the hr38a carb. and i am unsure what the tiny guy on the flange is for.

[speedycoop]

The tiny guy is probably for a primer hookup.

[Bazooo guy]

The tiny nipple could be a fuel return line to tank