D160 onan carburetor

[erickson13455 1]

I have a 78 d160 with onan.  I cant get the float and needle to adjust correctly.  The engine keeps running out of gas. I did work fine until just now.  I tried to adjust the float so that it was flat to top of carb, so that it would take more fuel in bowl to seat the needle,  No luck still runs out of gas.  If I take the needle out it will spit gas out the top of carb while running.  Do I need a new float or needle?  I have the "foam" type float.  Is the float getting stuck up?

 

Any ideas,

Thanks!

[woodchuckfarmer 333]

Is your fuel pump working good. Maybe its not getting the proper gas flow. Also check the tank  filter.--Wayne

[erickson13455 1]

Yes the pump is working.  I pumped it into a can while cranking the engine.  Put a new filter on it also. 

Is it possible to bend the tang on float to adjust it?

[the_nite_owl 15]

The old foam floats will swell from being exposed to ethanol in the fuel.  The swelling causes them to get stuck against the inside of the carb body.

I had the same issue on my D160 and replaced it with a metal float I found on eBay.

[erickson13455 1]

Did you replace just the float.  Do you use the same needle?

Thanks,

[the_nite_owl 15]

I did a normal rebuild which does not include the float and the problem still existed so I replaced the float.

They do not have to be changed together though.

[erickson13455 1]

Got the brass float installed.  It "runs" now, gets gas, but it runs rough, and backfires a lot.  What do I need to do now?  I tried adjusting the jets, started at 2 turns out.  Can't seem to get this right.  Do you have to adjust the new float.  I need help.  Thanks,

[JackC 617]

If it is backfiring it may be too lean. Do you have the service manual?

 

Initial Adjustment:
1. Turn main fuel valve clockwise until it just closes.
Do not open main fuel jet more than 1/2 turn beyond the maximum
power point as this could cause spark plug foulingetc.
2. Now open main fuel valve 2 turns counterclockwise.
3. Close idle valve in same manner and open it one
turn (counterclockwise).
4. This initial adjustment will permit engine to start
and warm up prior to final adjustment.

Final Adjustment:
1. Turn main fuel valve in until engine misses (lean
mixture), then, turn it out past the point where
engine runs smoothly until engine runs unevenly
(rich mixture). Turn valve to mid-point between
lean and rich so engine runs smoothly.
2. Hold engine at idle position and set low speed
adjustment screw (Figure 8) until a fast idle is
obtained (1200 rpm).
3. Hold throttle in idle position and turn idle adjustment
valve in (lean) and out (rich) until engine idles smoothly.
4. Reset low speed adjustment screw so engine idles at 1200 rpm.
5. Release throttle - engine should accelerate without
hesitation. If engine does not accelerate properly,
readjust main fuel valve by turning out slightly.
Important: Do not open more than 1/2 turn beyond
maximum power point.

 

Edited January 1, 2016 by JackC

[erickson13455 1]

Do you adjust the valves with the air filter and blower on, or off.  I got it to idle pretty decent.  When I try to throttle up it runs rough and will not run at max RPM.  How do I know if it is rich or lean.  On the main screw I went from 1 turn out to 5 turns out.  It will not stay running at full throttle?  It seemed to be able to run at about half throttle with the air filter and blower on it, but not at full throttle.  If there is a tad bit of white smoke in exhaust is it lean or rich?

I have never replaced the gasket in the carb.  It is in good shape, but will that cause problems.

 

Thanks,

[erickson13455 1]

I have never checked the points, I think I will check those.  Will bad points cause it to miss at full throttle, but run at idle just fine?

[erickson13455 1]

I checked the points and they look shiny clean.  I measured about a .018 gap at open.

I put on new spark plugs.    

Will not stay running at full throttle and backfires.  Is backfiring to rich or too lean?

I measured the coil.  ~3.8 ohms, ~15,800 ohms at plug wires.

What else needs to be checked or replaced.  Gaskets?

Thanks,

[gwest_ca-(File Mod) 11,510]

Have had a bad condenser lead me to believe I had a fuel problem causing the backfiring at certain rpm's.

 

Garry

[erickson13455 1]

Well finally got the condenser and installed it.  It runs fairly well now. 

 

Thanks for the tip.