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Need Help With My Ss16 Onan Bf Ms


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#1 PappyH OFFLINE  

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Posted August 15, 2012 - 07:21 PM

Ok my ss16 has been running kind of rough lately so today I decided to bring it in and see what was wrong. I ended up changing the carb, and intake manifold with one I had on the shelf that was supposed to have been rebuilt. Now the problem is I can't get any gas into the carburetor. I have never done anything to an Onan fuel pump and have no idea where to start. Need Help guys!

Bryan
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#2 Delmar OFFLINE  

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Posted August 15, 2012 - 09:10 PM

I took a couple of pics of the onan carb i have in a Case manual. My 16 hp onan has the same carb as my old sears Onan did. I Hope this helps.
Also, there is a manual for your motor on this site. Just click on manuals in the top section of the homepage, then click on engine manuals, the go to the one for sears suburban 16 hp i think. You can also find a manual for your motor on line, just do a search for the onan motor, good luck, i hope this all helps.

That sears of yours is a fine olds tractor with plenty of power and attachment options to choose from.


[attachment=40908:100_8712.jpg][attachment=40909:100_8713.jpg][attachment=40910:100_8714.jpg][attachment=40911:100_8715.jpg][attachment=40912:100_8716.jpg]

Edited by JBBR, August 15, 2012 - 09:20 PM.

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#3 John@Reliable OFFLINE  

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Posted August 15, 2012 - 09:23 PM

Ok my ss16 has been running kind of rough lately so today I decided to bring it in and see what was wrong. I ended up changing the carb, and intake manifold with one I had on the shelf that was supposed to have been rebuilt. Now the problem is I can't get any gas into the carburetor. I have never done anything to an Onan fuel pump and have no idea where to start. Need Help guys!Bryan


I would start there, that said I would go back to the old set-up that you knew worked, and rebuild it. Plenty of good parts and service manuals available for down-load on Onans engines on the net for free. Make sure carb has the Brass float, and believe it or not searspartsdirect has a lot of the parts, that come from Onan but cheaper than them.I saved over 100 bucks last parts order, that was ordered at sears but drop shipped from Cummings(Onan) Also check/replace gas line & filter
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#4 MH81 ONLINE  

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Posted August 15, 2012 - 10:40 PM

The Onan service manual is here on GTTalk.
http://gardentractor...ce-w-opt-parts/

I just looked, there are 250 manuals just in the engine area. Geez, that's a lot of info.
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#5 Hugh OFFLINE  

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Posted August 16, 2012 - 10:40 PM

Theres two things to do.

1. swap in a brass float and make sure its adjusted properly (1/4-1/8")

2. take apart the fuel pump on the side of the carb, and dap your finger in motor oil (new or old) and spread it around the perimeter of each gasket, this will make the pump seal up and pump strong again.

Also, when swapping around carbs and intakes its important to make sure any gaskets are in good condition and not broken. Also make sure your fuel filter isnt clogged and the line doesnt have any restrictions in it.
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#6 dstaggs OFFLINE  

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Posted August 16, 2012 - 10:57 PM

Have been having some with my 16 onan , now I put tank on top a let it run.LOL ps have to take time to rebuild the pump.

#7 Hugh OFFLINE  

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Posted August 16, 2012 - 11:15 PM

The gasket oil trick has worked for me both times I have done it on an Onan pump. It takes 5 mins start to finish. Dont bother buying the kit

#8 PappyH OFFLINE  

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Posted August 17, 2012 - 06:41 PM

Went out today and cleaned the carb again and took the fuel pump apart to try Hugh's trick. Pump did start working and everything was great for about an hour and then it started to miss and just stopped. Wouldn't restart and it is at the very back of my yard will have to put the charger on my yard pro and go pull it up to the shop. May just look for a deck and front plow for the yard pro and let the onan sit for awhile before I get mad enough to throw it in the lake!

#9 olcowhand ONLINE  

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Posted August 17, 2012 - 06:43 PM

I prefer to just add an electric fuel pump. That avoids fuel getting into the oil if a diaphragm goes bad in the vacuum pump.
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#10 Delmar OFFLINE  

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Posted August 17, 2012 - 06:48 PM

If it ran fine for an hour, did it run out of gas? Did the fuel filter clog up?

Until i went ahead and ordered the kit for the carb. on my sears Onan, I used to have to prime the pump by applying manual air pressure at the gas tank. I also learned from the guy i bought the parts from (Gary's Place) that the fuel pump on these can be a problem and you should use a easy to pass thru fuel filter for them.

I think olcowhand has some good advice too.

Edited by JBBR, August 17, 2012 - 07:00 PM.

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#11 PappyH OFFLINE  

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Posted August 17, 2012 - 07:58 PM

It didn't run out of gas and I won't know about the filter or anything until I get it back up to the shop which may not be until Sunday.

#12 Hugh OFFLINE  

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Posted August 17, 2012 - 10:46 PM

I prefer to just add an electric fuel pump. That avoids fuel getting into the oil if a diaphragm goes bad in the vacuum pump.


I have had 3 Onans with the diaphragm pump and 2 tecumseh's with similar pumps and never had an issue. Also, it is hard to find an electric pump that feeds at a slow enough rate to work well with the Onan carbs. Based on my experience.
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#13 John@Reliable OFFLINE  

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Posted August 17, 2012 - 11:06 PM

Might not even be fuel related if it just stopped like that, I would be testing coil.

Back to fuel, I had a problem a while back, where it would run good, then miss, but never completely stall out, drove me nuts, until by accident I found a cracked little O ring on the needle valve when I went to clean it, replaced it and all was good to go, like new.
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#14 PappyH OFFLINE  

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Posted August 18, 2012 - 10:13 AM

Got back to it sooner than I thought. I believe I need to get a new set of points and a condenser before I go any further on the fuel issues. Now where to get them at a reasonable price. Thanks to all for the help you have been giving me.

Hugh I know you love these old Onans but when ihis one gets runing again I believe I will find a new home for it.

Bryan

#15 PappyH OFFLINE  

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Posted August 18, 2012 - 07:50 PM

Progress report: Pulled another points set out of my parts engine and cleaned them up real good. Put them in and started right up. Needed a little tweeking in the carb but ran for about an hour mowing the back yard. Still wants to hunt when not under load so not perfect but way better than it has ever run. Will need to order a new set of points and a condenser but not sure where to get them.
Anyone have an idea where to get them? Hugh...ran good enough I may keep it for awhile after all.

Bryan




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