Flush tank, drain lines, clean carb bowl

[Forrest Carver 46]

My D160 barely starts and doesn't stay running. Fuel is splashing out of the carb, lots of it. It was suggested that some debris passed through the carb inlet valve. The suggested fix is to flush the tank and replace fuel lines and filter, then clean the carburetor bowl. I think I can handle the first part, but I'm a little leery of pulling the carb without some advice/direction.

 

[lynnmor 5,646]

I'm guessing that you have a 16 HP Onan, download the manual here.

[Forrest Carver 46]

Excellent, thanks. This should get me going.

[ri702bill 4,555]

2 hours ago, Forrest Carver said:

then clean the carburetor bowl.

Just MIGHT be a tad more than that- The inlet is the needle and seat, regulated by the bowl float. Get a GOOD quality OE carb kit, pull it apart and clean it well. Check the float to see (hear) if it is fuel logged. If so, it does not shut the flow of gas off, and will never until it is either repaired or replaced. Is that the vacuum fuel pump on the front of the carb? (not that familiar with Onans) could be worth your time to pull that apart too - could be debris inside.

Onans are infamous for the intake manifold gaskets #24 not sealing, resulting in vacuum leak(s).

Edited September 16, 2022 by ri702bill

[pacer 3,015]

The 'needle' in the carb is'nt sealing off -- piece of trash/worn/etc.

 

To inspect this or replace you only have to pull the carbs top part off, that will lift out the float attached to it. Its such a simple thing to do, I would pull it and inspect the needle and seat, if it has the brass float then also ck it to see if it has got a leak (put it up to your ear and shake it and see if any liquid sloshes around) and the bowl of the carb for debris, do a good flushing with carb cleaner and reassemble.... If it still does it, then you'll probably gonna need a new needle/seat.

 

If you arent pressed to need the tractor then go ahead and order up a 'Kit' for it, Do a search on the bay for an Onan B43 carb kit\

 

I see @ri702bill has beat me to it......

[ri702bill 4,555]

1 minute ago, pacer said:

you only have to pull the carbs top part off, that will lift out the float attached to it. Its such a simple thing to do,

Kind of like a 1960's GM Rochester one or two barrel 6 cylinder carb......

[lynnmor 5,646]

That carb has a fuel pump built right on the side of it, so there are additional places for gas to come out. 

[Forrest Carver 46]

Thanks all. I took it apart, cleaned it, and put it back together. It did appear the needle was pretty loose in its seat and could get stuck easily, wedging the float down. But the float is not full of gas. It's running OK now. I'll order up a kit just in case it happens again and I can do a more thorough job.

Edited September 16, 2022 by Forrest Carver

[Forrest Carver 46]

Carburetor problems continue unfortunately. The machine ran OK on a full choke, but required constant choke adjustment to stay running so I couldn't really use it. Upon taking the carb apart, I broke a corner off the top cover (see highlighted section below.) Actually, it looks like it was already broken once as there was some hard black goo all along the side of the broken piece, JB Weld maybe? I assume it would be impossible to find this replacement part? Maybe I can JB Weld it again?

 

Can I just replace the entire carburetor with a modern aftermarket one?

[lynnmor 5,646]

I would try to find a good used one or maybe you could find a good welder that would tackle the job. Converting to a later model carburetor and adding an electric fuel pump is a good idea but again, try to find a good used one instead of Chinese junk.

[oliver2-44 7,436]

Contact A-Z one of the vendors here, he may have a good use top piece or complete carb 

[Forrest Carver 46]

Thanks for the advice. I will contact A-Z and price out a complete assembly. I think due to the issues I was already having with the carburetor it makes sense to replace the whole thing.

 

I really just need to get the horse running to test it out on snowblowing or plowing my driveway. I would hate to put too much money into it, only to discover that it can't handle my steep driveway. As much as I'm loathe to use Cheap Chinese Crap, I would go that route temporarily to save money, just to see if the Horse is up to the task. If it is, I would happily put money into an OEM or good used carb and replace the cheapo.

 

-How can I determine compatibility for a newer model carb and fuel pump?

-What is involved in a complete carb replacement? Is it something that a just-below-novice could handle?

 

[lynnmor 5,646]

1 hour ago, Forrest Carver said:

Thanks for the advice. I will contact A-Z and price out a complete assembly. I think due to the issues I was already having with the carburetor it makes sense to replace the whole thing.

 

I really just need to get the horse running to test it out on snowblowing or plowing my driveway. I would hate to put too much money into it, only to discover that it can't handle my steep driveway. As much as I'm loathe to use Cheap Chinese Crap, I would go that route temporarily to save money, just to see if the Horse is up to the task. If it is, I would happily put money into an OEM or good used carb and replace the cheapo.

 

-How can I determine compatibility for a newer model carb and fuel pump?

-What is involved in a complete carb replacement? Is it something that a just-below-novice could handle?

 

 

I would never install a used carburetor before disassembling and cleaning the last guys dirt out of it.  Only on rare occasions does a carburetor need replaced, only breakage or extreme wear is what ends their life.

 

To update, the governor linkage may be an issue to work out, I am not sure what is required there, it may be fine as is. Of course you need to measure the bolt holes and the opening in the manifold.  Any low pressure electric fuel pump can be used.

[peter lena 6,469]

@Forrest Carver  have any fuel filters on that set up ? have 2 on each of my horses , large one close to tank , smaller one  closer to carb, also add STAL BIL  fuel treatment  to every bit of my fuel , and use ethanol fuel , no crud of any kind in my carb bowls , clean / clear , instant / quick / easy starts .  pete

[Forrest Carver 46]

Hi All, 

 

I appreciate the advice. Yesterday I used Epoxy Double/Bubble to weld the corner of the top cover. It looks like it should hold up well although I still need to file down the surface flat so it will interface without a gap.

 

I also received the carburetor rebuild kit yesterday and replaced the main jet & needle/spring. Boy, those jets are soft metal! After putting in the new gasket, I'm hoping that does it. I really don't want to remove the bottom half of the carburetor, it looks pretty time consuming.

 

I use Sta-Bil in my fuel, and I do have one fuel filter in the middle of the line leading from the tank to the carb, but the rebuild kit came with another fuel filter so I guess it wouldn't hurt to add another one in. Thanks for the tip.

 

Best,
Forrest

[peter lena 6,469]

@Forrest Carver  the general consensus of ethanol fuel is that it is bad stuff , what it is made up from  is the issue,  that is effecting  older fuel line breakdown , that and a dirty unfiltered fuel tank . having  changed over to clear vinyl fuel rated hoses , has eliminated that rubber hose break down. my fuel tanks have new  valves in them , and I  only use ethanol fuel . every bit of my fuel gets STA-BIL  treatment . there is no debris in my carbs . same det up on my generator , starts up at 3600 rpm , never thought it was the fuel . but related hose breakdown , clogging passages . eliminate , rubber hoses , with vinyl  ,  just my own experience , make a point of making issues go away , pete            

[Forrest Carver 46]

Finally got around to putting it back together. The weld held up and fuel is flowing out of the rectangular hole on the bottom half of the carburetor when the engine turns, but the bowl is not filling with fuel. I have verified that the float/needle both move freely, and the float rests at the bottom of the carb, therefore the needle is not plugging the entry hole. It doesn't appear that fuel is getting through the jet. Although it's brand new and properly installed. Any ideas?

 

Forgive my lack of proper terminology.

[lynnmor 5,646]

41 minutes ago, Forrest Carver said:

Finally got around to putting it back together. The weld held up and fuel is flowing out of the rectangular hole on the bottom half of the carburetor when the engine turns, but the bowl is not filling with fuel. I have verified that the float/needle both move freely, and the float rests at the bottom of the carb, therefore the needle is not plugging the entry hole. It doesn't appear that fuel is getting through the jet. Although it's brand new and properly installed. Any ideas?

 

Forgive my lack of proper terminology.

Does the float actually float or is it full of gas?  Is the float made of brass or a plastic?  Did you adjust the float as shown in the manual?  Can you take a photo of the "rectangular hole?"

[Forrest Carver 46]

The float is brass and not full of gas, but I did not adjust it, simply replaced the jet and needle

[lynnmor 5,646]

Did you try cranking the engine with the carburetor top off?  If you try it, carefully contain the area to keep gasoline from spraying all over, perhaps you could wrap a shop towel around and cover the carburetor with a jar.  I guess that the rectangular hole is the one in your photo, if gas is pumping out of it then all that is left is a blockage in the area under the needle and seat.  I guess that you are calling the seat the jet.