Broken Carb Jet

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eric136

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Jun 14, 2009
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After cleaning the carbs on my 1984 70 hp, I was screwing the low speed jet back into the carb and ended up breaking the head of the jet off after it was tight. Since the shaft of the jet is mounted in the carb, will this be a problem. I figured the main part of the jet is still there regulating the fuel delivery.

Eric
 
Mntom

Mntom

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Re: Broken Carb Jet

Do you mean you broke the jet or needle? If you broke the jet it depends on how deep the break goes. Maybe you could get away with it, but why did you tighten it up so much?
 
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Daviet

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Re: Broken Carb Jet

If you still have the carb off, I would remove the broken jet and install a new one. The broken one could come loose and cause problems at a later date.
 
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eric136

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Re: Broken Carb Jet

Well, I actually didn't know that I tighten that much. Prior to cleaning the carbs and while the carbs was still mounted on the motor, I removed the jet to see if it was clogged. While in the process of removing the jet and after initially "breaking loose the jet" there was a spot that was hard to turn the jet out for whatever reason. When screwing the jet back and it became difficult to turn, I thought I was at that "sticky" point, where in fact it was bottomed out. I can't image it being too easy to get the jet out now.
 
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jonesg

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Feb 22, 2008
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Re: Broken Carb Jet

Give it to a machine shop before you make it worse, ask them to run a tap through the threads after they get it out. Thats what you should have done instead of trying to force it.( a tap).
They'll probably use a reverse drill bit to spin it out.
 
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eric136

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Re: Broken Carb Jet

I guess my real question is since the shaft of the jet is seated, will it cause any problems. It is still regulating fuel, its that there is no screw head to screw the jet out. Is this something I can let go until I have to do some kind of work to the carbs again. I don't know what the chances are of having the threaded part of the jet back-out without the screw head being present.
 
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Sixmark

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Jul 11, 2010
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Re: Broken Carb Jet

It's really your choice, you can run it and hope it doesn't develop inot a big issue, or you can remove it and replace it and KNOW it's not going to be a problem.

I realize that everyone likes to save money when they can, but there are certain areas where saving a buck now ends up costing you more in the longrun.
 
Mntom

Mntom

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Re: Broken Carb Jet

eric136 said:
I guess my real question is since the shaft of the jet is seated, will it cause any problems. It is still regulating fuel, its that there is no screw head to screw the jet out.
Click to expand...
I am confused. Is this a needle or seat that is broken?
 
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eric136

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Jun 14, 2009
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Re: Broken Carb Jet

It is officially called the 'idle orifice' according to the parts diagram. I did not remove the needle valve when I rebuilt the carbs.
 
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Daviet

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Re: Broken Carb Jet

If you have idle orifices, what needle valve did you not remove?
 
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eric136

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Jun 14, 2009
Messages
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Re: Broken Carb Jet

Daviet said:
If you have idle orifices, what needle valve did you not remove?
Click to expand...

UHHH good point, after looking at the parts diagram again, I see the needle valve is for the 75 hp models and the idle orifces is for the 70 hp. I guess thats why I didn't remove the needle valve.
 
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boobie

Supreme Mariner
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Nov 5, 2009
Messages
20,826
Re: Broken Carb Jet

If it's just the jet itself and NO NEEDLE valve just leave it in there. Just make sure there is no debree in it. If you want to ever take it out again that's a whole different story. Were you using the right jet screw driver ?
 
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funk6294

Petty Officer 1st Class
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Apr 26, 2009
Messages
294
Re: Broken Carb Jet

Replace it. Its already appart and you know that it is not correct, so you will constantly be thinking about that and wondering. Also most of the jets I have seen have a small bowl or funnel shape in the head and that is important to how the jet flows. That bowl helps to smooth the flow of the fluid prior to entering the oriface. Without it the transition will not be smooth and the jet will likely not flow as much as before.
 
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