# 16 hp Onan issue



## oncewaslost1982 (Nov 14, 2006)

Hi all, still havent figured out that dang tecumseh issue. On to another project for a few. 

I have a 1976 Sears ss/16 garden tractor that I got from my grandfather. It has a twin cylinder air cooled Onan engine. I was unable to get it to run for the longest time without pouring gas in the carb and last night for the heck of it I spayed some engine starting fluid in the carb and started it up, kept it running for a minute by spraying fluid into the carb and it shut off. So, I put the choke on full (this engine has a manual choke) and turned the key and it started without any priming at all, and it will stay running. It idles really well and rather quietly too. It kind of sounds like a vw engine. Anywho, if i raise the throttle to mid speed it runs ok, but intermittently pops through the muffler, not very often though, and if i raise the throttle to high it will run for a minute and then try to shut off, bring the throttle back down and it does fine again. But the thing will not start or stay running with the choke off. Does all this make sense? I have described the situation to the best of my ability. I am wondering why it will run with the choke engaged but will not run with the choke not engaged? While it is running with the choke if i try to take the choke off then it will die. Any ideas?


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## ZukiJon (Nov 15, 2006)

Needs a good carb cleaning, and tune up maybe.

Jon


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## hdman97 (May 25, 2006)

I agree with ZukiJon clean the carb,better yet
rebuild the carb.
Don't use that starter fluid,it washes down the cylinder.
Could cause problems down the road.


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## oncewaslost1982 (Nov 14, 2006)

OK I got it to run without the choke. I took off the top of the carb and cleaned the holes in the main jet and it started up without the choke. It intermittently misses throughout the rpm range and since I ran marvel mystery oil in the gas, it smokes a good bit sometimes. What do I need to do to get it stop missing and run smoothly?


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## ZukiJon (Nov 15, 2006)

Did you put new plugs in it?


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## oncewaslost1982 (Nov 14, 2006)

Nope. I was just excited to see it come to life. I will get in there and check the plugs out. What all is encompassed in a tune up on one of these engine? Thanks for all the help thus far everyone. Would the fact that it needs a tune up and is running like crap cause it to smoke? Running too rich? Lean?


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## big ed (Jul 29, 2006)

this engine is old enough to have points and condenser and besides plugs that is very important to the tuneup and may have alot to do with spitting and popping at higher rpms also oil change and air filter usually are part of the tune good luck


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## hdman97 (May 25, 2006)

I think if the main jet was cloged, the rest of the carb should be gone over
soaked and maybe rebuilt.
As others have said change the plug and oil,and be sure the gas is fresh.
That oil in the gas is why it is smoking.Sears should have any parts you need.
With a little effort you should have a nice running engine.
Some of the older engines are better the the new ones. IMO


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## oncewaslost1982 (Nov 14, 2006)

actually sears carries very few to no parts for this old of an engine. Where might I source a points and condensor set? Anyone have a set to sell? Any sources for carb kit?


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## oncewaslost1982 (Nov 14, 2006)

I am going to put new plugs in it tomorrow and see if that helps.


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## oncewaslost1982 (Nov 14, 2006)

Oh yeah, already changed the oil too. That 5+ year old crap that was in it was obviously in need of changing. I used 10w-30 in it.


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## oncewaslost1982 (Nov 14, 2006)

Found a source for a carb kit. But no luck locating new points/condensor set.


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