Calling All Engine Techs ONAN Needs the AED

[HorseFixer 2,012]

She sputters and pops but no workey. Will post a movie after a bit.

~Duke

[HorseFixer 2,012]

Ok Its getting late Got the Movie Done Please Give Me Your Thoughts Fixin to Cook New Years Dinner

But Will be Cking back for your feedback.

Thanks Duke

[wovennut 44]

On my three 520s, the inlet fuel line comes in on the bottom of the fuel pump. Don't know if that makes any difference or not. Happy New Years

[smoreau 658]

Hay Duke! I was enjoying some of your Apple juice watching your video. Try hooking up a Battery instead of the charger, it will have more amps then the charger will put out and still maintain 12Volts. Also is the onen have electronic ignition ? if so you have to ground it to shut it off, open for running.

[HorseFixer 2,012]

On my three 520s, the inlet fuel line comes in on the bottom of the fuel pump. Don't know if that makes any difference or not. Happy New Years

Thanks Wove and happy new years to you too. The po had broken the line pecker thingy off the pump and I JB welded it shut and used the other two ports. As you can see Im getting fuel when I choke it with my hand. It acts like its out of timeing below is a picture of the Cam Gear and Crank Gear as you can see The Cam Gear is at 6:00 oclock and the Crank Gear is at 12:00 oclock this was written by TJ from Onan Parts .com and when they are aligned the pistons are 1/4" down from Before TDC and thats how mine was exactly. Below is a PDF File of TJ's How to Rebuild your ONAN Engine.

Cheers ~Duke

How to rebuild your Onan engine.pdf

[MalMac 1,331]

Duke quit using that starting fluid and use something with way more bang for the buck. APPLE JUICE !! Oh Yeah!! If it won't fire on that, it won't fire on anything. Keep plugging away.

[Kelly 1,029]

Duke hook up a batt. before you fry the ign. pick up, they are not cheap, and use carb cleaner or brake clean to start it, NOT starting fluid.

[MalMac 1,331]

Hey Duke Kelly's right stay away from the starting fluid. That stuff is just plain bad news for gas engines. I have been around big Diesels my whole life and I have seen guys ruin Big Diesels with that stuff. Yes there are times you have to use it to get big Diesels going but you got to use your head. I have seen small engines just plain grenade using starting fluid. That explosive of vapor plus and electric spark can add up to alot of damage and the possibility of someone getting hurt.

[bobert94 38]

Duke sounds like it wanting to run You might want to dump a thimble full of fuel directly down the carb and hold the throttle open a little this will let more fuel get to cyl. i dont think stsrting it off a battery charger is ideal without a battery. If still does'nt go id check compression with guage. throttle and choke need to be wide open when doing so, you shold have at least 100 psi. i dont know if there is away to change ign timing with the electronic ign? good luck

[HorseFixer 2,012]

Well lemme say that you guys are dead on with the Battery Idea. I have used the Battery Charger on easy to start engines but this aint it! The starter dont Lolly Gag and doesnt stall out like when museing a Battery charger! The Scuemacher I was useing is 200 amps too! The battery charger is much faster turning over also. It was wanting to pop off a lil better but something is still a lil off??? Keep the ideas comming thanks everyone fer yer help. Tim Ill try the apple juice Next!

~Duke

[sorekiwi 761]

Bob, just replied to your other thread.

Why do you ask the same question in two different threads? :banghead:

[HorseFixer 2,012]

Bob, just replied to your other thread.

Why do you ask the same question in two different threads?

Sorry Mike I will go look! :bow-blue:

[HorseFixer 2,012]

Bob, just replied to your other thread.

Why do you ask the same question in two different threads?

sorekiwi Said in Prior Post In My Rebuild thread.......

A couple of things spring to mind:

You dont say that you have checked for spark. An Onan will make a good spark even if you turn it by hand, just power up the coil and urn it by hand and look for the spark. There are TDC and ignition timing marks on the flywheel so when you see the spark, check the marks to make sure the trigger is timed right.

Duke: Mike I plan on removing the flywheel and checking the Trigger Ring 8-1 & 8-2 in the manual. I smell a Rat here.

Instead of powering the ignition through the plug like you are doing, I would put the jumper directly to the poitive side of the coil. I dont remember if the 520 has its ignition feed wired through the oil pressure switch or not, jumping directly to the coil will bypass this if it does.

Duke: Good Idea I Will do this.

Looking at your picture of the valves while you were adjusting them I see a .05mm feeler guage. Did you set your inlet valves to .005" or .05mm??

Duke: uhhhht oooooooo I think I Bucked Up Right Here

You dont seem to have any means to check oil pressure set up on your engine. I would be at least setting up a lamp to operate off the oil pressure switch, and I would crank up oil pressure with the ignition off before firing the engine. A "proper" engine with pressure fed bearings will eat itself really quick running with no oil pressure, remember that on the Onan everything depends on the oil pump to deliver lube, even the one cam bearing that is splash lubricated is splashed with oil that is pumped to the top of the engine.

Duke: I am getting good oil pressure the switch switches continuity on my ohm meter.

Did you look closely at the inlet manifold while the engine was apart? They are a little infamous for developing an air leak between the two halves, on mine I drilled out the rivets, drilled and tapped for (I think) 6-32 screws, and resealed it.

Duke: I think mine is okay, I seen that when I was polishing and seen those rivits isnt that a crock of chit.

Also isnt there some sort of vacuum fitting on the manifold? I dont remember what it is for, is yours blocked off or hooked up to whatever it is suppossed to hook up to?

Duke: Mike that's manafold vaccum Ihave tube and it is blocked with bolt in tube.

Thats all I got right now.

Mike I thank you for your help!!!!! I think my problem are in the following......

Valve Clearence & Trigger Ring and Electronic Module Gosh Dangit!!!! Wheres my apple Juice AT!!! Guess what Ill be doing all day tomorrow and possibly monday all I can say is!!! Are We Having Fun Yet?

See you guys in a couple days Duke over & Out!

[HorseFixer 2,012]

The whole problem as I said in the movie acted like Timing.... Well as it turns out Valve and Ignition Timeing.. Not Cam & Crank Timing, I sure dont mind wrenching as long as I'm learning something about this Onan which I truely am. Since the intake valve is not opening far enough it wont get enough fuel will it? "whistle: funny how things begin to make sence. Thanks Again Mike!!

~Duke

[sorekiwi 761]

I'd make sure you have spark before pulling off the flywheel Bob. The trigger thingy is keyed to the crank, so its hard for that to be in the wrong place. If you turn the engine by hand and stop as soon as it sparks you can look at the timing marks on the flywheel to see if the timing is correct.

Your tight valve clearances will actually make the valves open further. But it will affect their timing, they will open earlier than they should and close later. I'm not really sure why your plug isnt getting wet. Maybe all the fuel/air mix is getting pumped straight onto the muffler with the extra cam overlap you have now, or possibly there is so much overlap that not enough vacuum is being created to suck it into the cylinder?

Personally I like to try and work out exactly what is wrong so I try to fix one thing at a time. I'd make sure I had spark first, if I did, then I'd do the valve clearances, and only then would I worry about ignition timing.

[HorseFixer 2,012]

Well it is 4:00 a.m. and I removed the Intake, exhaust, engine shroud around flywheel. I ran the tests on the timeing and it was off by 1"etween those marks on shroud till it went to full batt voltage. Removed flywheel and what had happened is I think I inadvertantly got the timeing ring thingy outta wack cause it was indeed off by 3/8" (it was pushed in to far and not in alignment with keyway (keyway wasnt in the rings groove) Fixed that reinstalled flywheel and shroud checked again and perfect. I then went for the valves. They were off trust me! 3 thousandths on intake and 11 thousandths on exhaust reassembled everything and had high expectations that it would start right up NOPE no spark WTF I checked coil by the book and I dont get Jack Chit Diddley outta it. I ran the ohm tests and they are otta range. Looks like Im dead in the water till I get a coil. Question will a Kohler Coil work? at least for checking out engine?

Thanks Duke

[smoreau 658]

A twin cylinder coil should work from your spare KT17 engine. give it a try and let us know what happens. Happy new year Bob and best wishes to ya and your family!

[rmaynard 15,519]

Did I hear you say that you had the condenser connected to the (+) side of the coil? I've never worked on an Onan, but all the Kohlers I've ever worked on had the condenser on the (-) side.

[sorekiwi 761]

Did I hear you say that you had the condenser connected to the (+) side of the coil? I've never worked on an Onan, but all the Kohlers I've ever worked on had the condenser on the (-) side.

Onans have the condenser on the +ve side of the coil (at least on the electronic ignition versions).

I think there is a discussion about why on Chucks site a while ago. :)

[Kelly 1,029]

Like Scott said any twin cyl. coil will work, now get a batt. hooked up before you ruin the ign. pick up, if you need more cranking power hook the charger up to the batt. and Like Mike said hook up a cheap oil gauge, or a light I have a oil gauge I use on every car engine I rebuild, unhook the ign. and crank till oil press, comes up, and with the starting fluid it can fire and try to turn the engine backwards, especially if its out of time, breaking parts, NEVER use starting fluid on small engines.

[HorseFixer 2,012]

Thanks Guys its 12:45 and Im just getting up and around. I cant take those late nights like I used too. The coil worked just fine befor I took it apart the last time? and at that time I was useing a Battery I prolly weakened it when I was useing the charger? Well its spilt milk now so I will go out and try the one I have off the spare KT17 I have, and

see whats up. Happy new years to all, hopefully I can get it running.

Thanks ~Duke

[Sparky-(Admin) 21,347]

This topic has us on the edge of our seats Duke....so shake off the hangover and get crackin!

Mike............

[HorseFixer 2,012]

This topic has us on the edge of our seats Duke....so shake off the hangover and get crackin!

Mike............

Mike Im Tryin! A Great New Years would be to here this engine run. Ok I went out and changed the coil and put the KT17 coil on the onan I now have spark but it sputters the same as before. I checked my Trigger ring and Ignition Module timing and it is good compare with manual and movie. I gapped the intake valves at .005 and the exhaust at .013 first did the left hand cyl facing flywheel adjusted intake & exhaust then went one turn and did the right hand cyl and gapped the intake and exhaust per specs above. this thing is wearing me down.

~Duke

[ol550 830]

You trying to run that thing on apple juice? I'm really busy on the S C jr, but

if I can get it finished up in the next couple weeks I can slip up there and help out.

Don't know too much about the Onan's but can you put a timing light on it while you

are cranking it over to see if the thing is firing close to where it should. Give it a shot

it would let you know the ignition timing is correct or close. If it's off then you can go

from there. Mike

Posted before watching your video. Still try with a timing light and unhook the charger

when you do. Maybe the ignition doesn't like the high voltage you are getting from the

battery charger. And make sure you don't have any apple juice in the fuel.

[MalMac 1,331]

Duke just in case it's not a timing issue at all, have you poured any gas into the carb to see if it will fire at all? Seems you should be at least getting wet plugs. It's maybe a carb issue Onans are known for cantankerous carbs. Anyway just a thought. Even though you should not use starting fluid you would think it would at least let out a belch or backfire even if its timing. Have you pulled the carb apart to check and see if your float bowl is full? or at least got gas in it.