Low speed needle

[scrit9mm]

25r73. Rebuilding the carb yesterday, the manual read when installing the low speed needle (the one that sticks out of the front of the carb and controls the choke knob) you should screw it all the way in until the needle seats then back it out one turn.

When I was installing the needle it screwed all the way in until the rubber gromet hit the filter/shield that is attached to the front of the carb. Is this correct or should the tip of the needle have contacted something to stop it?

I have not cranked it because of a leaky fuel pump cover that is on order. I hope I did not forget something.

 

[CatfishMN]

Re: Low speed needle

Had that same motor. Turn it in until it seats, and do not force it. Then out 1.25 to 1.5 turns and then dial it in.

 

[kfa4303]

Re: Low speed needle

Hi scrit. This should help.

http://forums.iboats.com/showthread.php?t=167352

 

[scrit9mm]

Re: Low speed needle

How much of the needle is sticking out from the metal sheild that attaches to the front of the carburetor? I am not using this for a measurment to tune I am simply comparing my situation to others with this motor. I feel that the tip of the needle is not getting "set" the needle is just stopping due to the rubber grommet that is on the shaft.

 

[F_R]

Re: Low speed needle

If I am reading your question correctly, you have the rubber grommet on the needle shaft, and it is getting pinched between the knob and silencer cover. The rubber grommet is not supposed to be on the needle shaft, it is supposed to be installed in the silencer cover, that is the cover fits into the groove in the OD of the grommet.

 

[scrit9mm]

Re: Low speed needle

I will post a picture at lunch to help the description.

 

[scrit9mm]

Re: Low speed needle

Here are some pictures. The white plastic on the end of the valve is what is left of a leftover adjustment gear, I put it on to make the valve easier to adjust.

 

[AlTn]

Re: Low speed needle

as Lindy suggested the other day...flip the knob over and reinstall it on the shaft, make your adjustment to the mixture needle, then install the knob the correct way so that it can move 180 deg, either direction ie; it'll give you 1/2 turn richer or leaner. In the past, I've adjusted the needle using finger feel to find the bottoming point then back it out 1 1/2 turns w/o the silencer or knob in place.

 

[scrit9mm]

Re: Low speed needle

Again, I am not asking about getting the mixture correct. I am concerned that I left something out of the carburetor during the rebuild. The amount of the needle that remains outside of the metal cover that bolts onto the front of the carb is my concern. Everyone describes the seating of the needle. My concern is that if the metal cover that bolts onto the front of the carb was removed then I could screw the needle into the carb more than the metal cover is allowing me to. This has nothing to do with figuring the rpm for low speed, I am not to that point yet. As I said before, I feel that the metal plate that bolts onto the front of the carb is stopping the needle from screwing into the carb to the point that the tip of the needle seats itself.

 

[F_R]

Re: Low speed needle

There is nothing you could have left out to cause the situation. I suggest you pull the knob off and do the preliminary adjustment. Then see if the knob will snap back on. If not, the needle may be too short (wrong one). or somebody may have reworked the tip at some time, making it shorter. Or the tip is badly grooved. Or somebody in the past has wallowed out the seat by cramming the needle in too tight.

Bottom line: If you can get it adjusted, and the knob will still snap on, don't worry about it.

 

[scrit9mm]

Re: Low speed needle

Thank you F_R.

 

[nwcove]

Re: Low speed needle

There is nothing you could have left out to cause the situation. I suggest you pull the knob off and do the preliminary adjustment. Then see if the knob will snap back on. If not, the needle may be too short (wrong one). or somebody may have reworked the tip at some time, making it shorter. Or the tip is badly grooved. Or somebody in the past has wallowed out the seat by cramming the needle in too tight.

Bottom line: If you can get it adjusted, and the knob will still snap on, don't worry about it.

and if you do get it set up and working well, and the knob is jammed against the metal cover, try a few small washers or a very short piece of small tubing between the needle and the knob to give you some clearance. ( thats if theres enough spline, and the screw that holds the knob on is long enough)