Onan 16 hp. dies after running

[davedean 2]

My 416-8 starts, runs and dies after a few minutes. It has been progressively worse over 4 days (not running every day). It would start and run for a half hour or so, then just lose rpm and die. I'd give it a short rest then it would start right up and run. The intervals of running/dying have been  getting shorter. The last time I tried, it would run about 10 mins. and die, and would not start back up. I think carburetor, any clues/suggestions?

Thanks for any input.

Dave

[rmaynard 14,909]

Be sure that the vent on the gas cap is not clogged.

[Sparky-(Admin) 19,568]

Before you rip into the carb, start back at the fuel tank. The tank needs to be vented to work properly so try running it with the fuel cap loose. If thats not it then maybe the fuel shutoff at the tank is the problem. It has a small mesh filter screen that can get clogged up with crap, might be time to swap it out. Do you have a fuel filter? How long has it been in service?

It could be the carb still but I would start with these other items first.

Mike..........

[davedean 2]

The see thru fuel filter is full of gas, but I noticed at one time the filter was almost dry. I'll try all the "easy" fixes first. The fuel hose coming out of the tank looks cracked, but not leaking.

Thanks

Dave

Edited November 17, 2013 by davedean

[Martin 2,130]

if the fuel system checks out ok........

 

ignition could be giving you problems, immediately when it stops check for spark. older ignition components can be unreliable. not saying thats the answer but would be the next step if you can't find the issue........

[davedean 2]

it won't start at all now, unless I spray starter fluid into the carb, As soon as it uses the fluid it dies. The foam filter was pretty dirty, not oil soaked. I blew both the foam and paper out w/ compressed air. I bet it's time to pull the carb, what do you think? I checked the fuel pump, it's working.

Edited November 17, 2013 by davedean

[Martin 2,130]

Sounds like the ignition is good then. I think you have a blockage in the fuel system somewhere. The carbs are easy to check for junk in the bowl, if you are careful removing the top of the carb, the gasket could be saved.

Take a look at my 416 adventures thread, I had fuel issues and managed to clean out the carb with it still on the engine.

Sent from my iPhone using Tapatalk

[WH nut 553]

I would pull the fuel line off the outlet of the fuel pump before I start ripping anything apart

[davedean 2]

I called the previous owner about the problem, he told me to change the inline fuel filter. I blew though the old one and it seemed clear, but the new filter fixed it. 

Thanks everyone for all your help.

[Ken B 3,116]

Now I'd give your fuel tank a good cleaning and replace the fuel lines if they haven't ever been done....

[davedean 2]

I will do that. A little extra insurance is good peace of mind. What do you suggest would be a good cleaner for the tank? Thanks to everyone who posted

Edited December 3, 2013 by davedean

[dennist 139]

Any above options are great, I tried them over and over. My worker 416-8 made me pull my hair out, it may not turn out to be any of the above issues, yet any one of them could make your problem happen.

I got pretty good at tearing apart all tin, exhaust, intake, carb, replacing fuel lines, pump and filter, removing/cleaning tank, new intake gaskets, then started with electronics...key switch, coil/plugs/wires, ignition module, trigger, jumped every safety switch, etc. Each and every time it would start and I swear it sounded better and ran smoother, but when I would get on it and drive for a few minutes it ran terrible and would die out. Some times it would smoke like a train and other times just seem like it was going to blow on me, but every time after sitting it would start and run smooth....common sense was telling me one thing, but the thought of running over it with a dozer was really looking good to me, And I mean it!

I had it with that darn Onan and finally felt like others on here feel about them, but I could not walk away and let it win me, I atleast wanted to tear it apart to see what was making it run that way. All the wires looked fine, compression was around 115psi on both sides. Finally looking in the same places as earlier right behind the upper steering shaft I pulled the wires completely out just to reassure myself that it had nothing to do with those and......

Lets just say "I" personally can not put the blame on those darn Onans, atleast not this time, although every time someone talks negative about an Onan I somehow link the engine with the non engine tractor issues. Good luck and keep the keys out of the dozers until you get it fixed!

[WH nut 553]

He said a fuel filter took care of it, but you did have your hands full dennist, good find

[varosd 1,185]

Good post Dennist!

 

Davedean,

                 all above replys are great!  not sure if someone asked but is your 416-8 a Kohler or Onan engine? My 520 had sorta same issue, I tracked it down to the fuel tank. while I had fuel spurting into the carb. I replaced fuel lines/filter and pulled the gas tank out and lo and behold, as I drained the remaining fuel..the in tank filter was all plug up. I kept just adding fresh gas and did the gas tank Rock and Rye shake.  kept doing this and also opened up the drain and let fresh gas flush out (or just buy new drain plug)

started right up.   If it's an Onan, they do have carb issues.

[wheeledhorseman 573]

Having read the thread, and owning a !6hp Onan powered horse, there's a little mystery here in that when an Onan is running short of fuel in the carb bowl it starts hunting before the fuel runs out and it stops. All small engines with a governor do this to some extent but it seems to be very pronounced with an Onan yet it was not mentioned in the symptoms.

 

Hope it stays good for you now

 

Andy