Linkert hard starting

[fxe76]

Was having a hard starting problem on a 58FLH -- as per advice on the board i checked for and found a vacuum leak at the front O-ring on manifold --- in the process of vacuum check i noticed a hole in the back side of the carb body --- the hole appears to be original as from the factory --- it is about 1/4 inch in diameter and back about 1 1/2 inches from the air cleaner flange --- question is, what is the purpose of the hole and should it be open or plugged --- it is open now and appears to be drawing vacuum

[panfreak]

Sounds like maybe idle hole body plug? Is the hole threaded? ???

[fxe76]

no threads in hole -- it's just above the float bowl gasket

[57pan]

I don't have any idea what the hole is for, but if it's drawing unfiltered air into the engine that can't be good for it. What happens if you put a piece of tape over the hole? Does it affect the starting or running of the engine?

[Guest]

How about a "Vent hole"

[fxe76]

Plugged hole -- still very hard to start --- flat will not start when hot

[Rainjester]

You didn't mention if you fixed that intake o-ring leak or not. That's probably the source of your problems. Discussion on this is in a couple of threads and this symptom tends to lean towards intake manifold leaks. I'd get this fixed first to see if the problem continues. Besides, if you haven't fixed it yet, you take a risk at causing damage.

jester-

[fxe76]

Fixed that leak a soon as i found it -- all seems leak free now -- did reset points to 18 tho. and that seemed to help some --- still takes 20+ kicks to start.

[Cotten]

Sorry to get in on this thread so late...
The large hole on the side of the carb body is where air enters to mix with the main nozzle.
It must not be plugged, or your carb will not function above the idle range.
It may seem strange that unfiltered air enters there, but true.
I believe that the only HD Linkert that feeds the nozzle through the bore is the M88.

(Curiously, all Indian Linkerts are feed through the bore, and Scheblers before '40 often can be found either way.)

[fxe76]

Thanks Cotton --- That was my real question --- jus wanted to be sure i wasn't chasing a problem that didn't need chasing.

[PantoMine]

Just like Cotten said, DO NOT Plug that hole. The hole is there for a reason and it does allow unfiltered air to enter the fuel system, it is actually a bleeder for the nozzle above the main jet (fixed) and high speed adjustment needle. I'm guessing you have an M-74 1-1/2" Model B Linkert, if you look at the casting you will see that L&L had a "boss" in the casting where the unthreaded hole is drilled thru. There is also a seperate bowl vent hole drilled through the flange a little further toward the manifold side of that model Linkert, don't plug that either.
I'm also going to guess that you're over-all fuel system is running a little rich. If you have the high speed needle set about 1-1/4 turns out and have good throttle response at that setting (as opposed to popping, missing, backfiring) when you open the throttle then your problem is probably a "leaky" needle and seat, too much fuel in the bowl. The re-pop needles have a neopreme tip and come from Taiwan or somewhere and they leak. Make sure you set the float to specs (1/4") from the top of the bowl and that you get positive fuel shut off with the float up. If the outside of the carb is always a little wet and you have that constant "gassy" smell that's probably your problem. Another thing to look for is water in the gas, make sure you dump both the strainer and the nut at the bottom of the bowl.
Hot start tip, try holding the throttle about half way open, NO CHOKE at all.