A few simple carb questions

[carpenterken]

By doing some of the different self test, I figured out my # 3 cylinder on the 1976 115 was not getting fuel. I took that carb off an did a through cleaning job. I put her in the lake and she ran on all 4 again pretty darn good, but now at idle she has a bit of a spit back. Do these carbs have the slow speed needle valves? and do they need adjusting now that the carbs are clean?
I don't recall seeing any s/s needles. If not than how do I get rid of the spit back?

Also I fired up my omc 15 horse 1996 model just to find that it would not run with out the choke on. Off with that carb. Is the proper setting on that slow speed needle valve 1.5 turns out?

Thanks.
Ken.

 

[iwombat]

Re: A few simple carb questions

I'm pretty sure those are fixed jets. Did you remove the core plug and clean out the idle passages when you had it apart? If not, that's your problem. Give it a good soak when you've got it off too.

 

[jtexas]

Re: A few simple carb questions

Spitback is a symptom of worn reeds.

There's a thread on carb needle adjustments in the Engine FAQ section

 

[Dhadley]

Re: A few simple carb questions

If it's spitting back after the carbs were put back on I'd look at the linkage adjustment. Sounds like one of the butterflies is being held open. Make sure the roller isn't touching the cam follower.

 

[carpenterken]

Re: A few simple carb questions

If it's spitting back after the carbs were put back on I'd look at the linkage adjustment. Sounds like one of the butterflies is being held open. Make sure the roller isn't touching the cam follower.

Maby spit back is not the proper word for what its doing. It's more like a mild back fire at idle speed (it will kill the motor when it dose it) If I lift the warm up lever up it only barely dose it. could it be the timing is to far advanced?

I have read many past post and many of the faq's and, I think what your doing here is GREAT!
Thanks.
Ken

 

[HighTrim]

Re: A few simple carb questions

The throttle cam on engine is marked START. When warm up lever on control box is moved to START position (up), the START mark on the throttle cam should center on the cam roller. If it does not, turn the stop screw in your control box in or out to get the proper adjustment. The warm up lever adjustment should be checked and redone if required when the engine idle speed is changed enough to require throttle cable trunion adjustment. And like Dhadley said, to set the throttle and choke linkage, retard the throttle lever until the throttle cam follower roller does not touch the cam. Loosen the upper and lower carb lever adjusting screws to allow the return springs on the throttle shafts to close the throttle valves. Rotate the levers manually to make sure that the valves are in fact closed. then tighten the screws. Start your engine and run her at idle speed with the throttle closed. Snap out the throttle link and if it is adjusted correctly, with the engine idling, the RPM should not change.

 

[iwombat]

Re: A few simple carb questions

What you're describing sounds like a lean lag to me, which is why I originally mentioned cleaning the jets. Does it have this problem if it's partially choked?