Ranger 8: cleaned up and now problems???

[freshintulsa]

OK, I recently got a ranger8 with 70 hours on it from a buddy at work who doens't use it. It sat for the last 2 years with old bad gas. I was going to just get a carb rebuild kit, but the cummins/onan dealer gave me a good deal on a new carb so I just went that route. I put new plugs, wires, oil/filter, airfilter/prefilter, fuel filter, drained the gas tank, and filled it up with new gas. I put a new battery on and it cranks great. Problem is it wont start up.

I thought maybe some air in the fuel lines or something, opened the fuel lines before/after the pump and still nothing. It will start to fire, but just barely and when I let off the starter it will run for a second or 2... barely... and die. I took off the airfilter and looked in the carb, well gas will come up out of the carb into the air filter housing. I'm not the worlds greatest mechanic, but that doesn't seem right to me. Well, with the airfilter off it will start, and idle down after a few seconds as if everythings ok.


Anyone with an idea of where to look? I've looked at the manuals online and am thinking timing maybe, but I dont know. I'm gonna take a break from it for now, but please give me some ideas if you can on where to look.


Thanks, Doug.

[duaneb55]

Runs without the air filter but not with it? If I read that correctly, you didn't oil down the prefilter did you?

[freshintulsa]

Yes, I did oil the prefilter. Should I not have? I put a very light amount of oil on it and squished it around to soak it in evely. Isnt the purpose of this to catch the dirt better? just to add, I did check the gap on the new plugs, all my connections are tight, fresh gas at about 1/4 tank full. Any ideas? Im gonna go run some errands and then I think I'm gonna mess with the carb a little, maybe the idle mixture screw or something.


Thanks, Doug.

[duaneb55]

Pull the oiled prefilter off and try it again.

Only a tablespoon of oil is supposed to be worked into the prefilter evenly and then squeeze out the excess to the point the prefilter is barely damp with oil.

Too much oil and the air flow could be restricted to the point of flooding especially if the carburetor float level is set too high.

[freshintulsa]

First off, thanks alot for the help Duane, i really appreciate it.

OK, So i toook off the prefilter and no difference. It was totally dry by now, and I dont thnik it was too oily to begin with but who knows.

The only way i can get it to run is to take the air filter completely. When it does run it spits fuel out of the carburetor. Something isn't adjusted right and i'm no genius so does anyone have a direction i should look into for adjusting?

thanks in advance, DOug.

[farmall]

I took off the airfilter and looked in the carb, well gas will come up out of the carb into the air filter housing.

That's flooding, and sound like a stuck/misadjusted float or that there is a crumb between needle and seat. It is running rich so the only way to compensate is remove the air filter.

Even new carbs get bounced in shipping, so it's always worth checking float adjustment.

Ensure the float is seating and properly adjusted, and ensure any fuel adjustment screws are set as they should be.

I'm not familiar with that particular carb, but the symptoms are standard.

[NVW]

Maybe the excess oil is now plugging the air filter. It may have pulled the oil onto it.

[freshintulsa]

I dont think that there was any excess oil on the prefilter, but it was a good point and I thank you for pointing it out. therefore, I doubt that any extra oil is clogging the filter.

Im going to go ahead and check the float and see if its all adjusted and set correctly. Will report back tomorrow hopefully and see what happens.

Thanks again, Doug.

[duaneb55]

I took off the airfilter and looked in the carb, well gas will come up out of the carb into the air filter housing.

I missed this point last time. If the float level checks out OK, think about checking the valve adjustment. Intake valves that are too tight (not enough clearance) can cause "reverse pumping" of the intake air/fuel charge that is exhibited by fuel spitting back up and out of the carburetor. Partially closing the choke tends to increase intake vacuum reducing the effects.

[freshintulsa]

thanks again everyone. I will check the float and the valves.

Appreciate the help, hope I can get this figured out soon!!
Doug

[freshintulsa]

Just thought I would let everyone know I'm still working on this. I didn't check the float today but I think I've gotten it closer to being figured out. I'm thinking its the intake valves being out of adjustment. I put a rag over the end of the muffler and one side seems to be sucking in just a little bit every once in a while. Time permitting tomorrow I will check the valve clearances and see what that gets me.

Doug

[freshintulsa]

OK, some updates and more questions.

So a buddy came over to help who's into smaller motors and such. We checked compression and about 50 pounds on one side, and NOTHING on the other. I took off the intake and opened up the "valve cover" and we found a surprise. I'm not sure what you'd call it, but the piece that goes on the valve stem that you check your clearance against had fallen off.
We got it back on and checked the valve clearances and everything was fine. Hmmm... Well, pulling the spark plug on the side with no compression changed nothing, so it clearly is only running on one cylinder. We were thinking maybe head gasket, but who knows. I guess it could be a number of things, but we were a little intimidated being that pulling the head won't really do much since everything seems to be in the block and you'll have to split the case to get to anything.

Anybody have any ideas or things to check before ruling this a dead motor or thinking of an engine swap?

Anyone have any ideas on engine swaps? Any good engines to swap in?


My 70hour welder doesn't seem like such a good idea, but for $700 i think i got more than that in accessories/leads/rods.

Thanks again, Doug.

[freshintulsa]

Anybody have any ideas?

[duaneb55]

Well, this new information sheds a whole different light on the matter.

Time to pull the head on the dead cylinder and see if you've got a burned valve or piston or some other surprise.

FYI, the Onan is easy to work on.

[freshintulsa]

Will I be able to see whats going on if i pull the head, or do you have to split the case to see whats going on inside? I'm new to these flat head motors, or small engines in general.

Thanks again, Doug.

[duaneb55]

With the head off you'll be able to clearly see the piston and both valves (intake and exhaust) of that cylinder.
77039

[freshintulsa]

Ok. Had time to pull the head off today. Bent intake valve. The seats both look good, and the exhaust valve looks fine. I'm going to call cummins/onan monday and hope they have a valve and some gaskets in stock. I'll post back when i get it in and hope that it fixes it. I've got a little side job waiting on it that I was hoping to get done over the holidays.

Thanks again, DouG

[duaneb55]

I highly recommend you check with member onanparts.com as he typically has the best prices for new, genuine Onan parts - if you can wait until after the first of the year as his shipping is shut down until 1/4/2012.

Check these against the local Cummins/Onan shop.
http://onanparts.com/index.php?main_page=product_info&cPath=1_6&products_id=12
http://onanparts.com/index.php?main_page=product_info&cPath=1_7_19&products_id=18

[4sfed]

Ok. Had time to pull the head off today. Bent intake valve.

Are there any marks directly above the valve? The only way I know to bend a valve in a flat head engine is to drop something into the intake system . . . that eventually gets caught between the head and valve after finding its way into the cylinder. I would expect to see a few dents in the piston too.

Jim

[freshintulsa]

There were no marks on the piston, and the cylinder walls look factory new. I think what happened was that the valve cap (between the stem and lifter) came off at some point. This allowed the valve to maybe get pushed at a slight angle and came into contact with the head. I see no other damage and have the new parts.

The cummins store was actually CHEAPER than onanparts.com. I've got it all cleaned up and ready to go. tomorrow i'll pop the old one out and putthe new one in and hope for the best.

Thanks again for the comments and help, Doug.

[duaneb55]

There were no marks on the piston, and the cylinder walls look factory new. I think what happened was that the valve cap (between the stem and lifter) came off at some point. This allowed the valve to maybe get pushed at a slight angle and came into contact with the head. I see no other damage and have the new parts.
I would agree completely.


The cummins store was actually CHEAPER than onanparts.com.
That may be a first. For me anyway. I've seen the occassional new Onan item go cheaper on ebay but the Cummins/Onan guys tend to be quite a bit higher.


I've got it all cleaned up and ready to go. tomorrow i'll pop the old one out and putthe new one in and hope for the best.
Sounds good. Keep us posted. :drinkup:

[freshintulsa]

I was thinking about this... do i need to "lap" the valve with some compound even though its new? It would probably help it seat and seal better wouldn't it? Any one with some recommendations?
I was just going to suction cup it from the face and twist it by hand to the seat on the block.

Thanks agin, doug.

[duaneb55]

If the seat is undamaged and not pitted, lapping in with compound will clean any carbon off and is typically sufficient. I've done it on more than a couple occassions without problems. You'll see very quickly if the seat will need more attention than that.

You can check by filling the ports with solvent when the valves are reinstalled and closed to be sure. Very minor seepage is acceptable but running fluid calls for further action to prevent performance issues and a burned valve down the road.

[freshintulsa]

OK, i got the new valve in, set the gap on all the valves, and put it all back together. It seems to run great now. No smoke, idles down and up, no flooding, all good. EXCEPT, now i've got 90pounds of compression on the side i just redid, and now only 25-30 on the other side. :help:

When I first checked it before working on it, the one side was zero, and the other was 50 or so (dont remember exactly).

What should the compression reading be on this engine?

ALSO, the valve cap was off on the "good side" intake valve as well. I'm thinking that maybe this valve is slightly bent too. I guess I will pull that head off and check itout.

Man, what a strange trip this has been, so far.

[freshintulsa]

OK! I got my new valve for the other side yesterday and put it all back together and its all back in business now. 90 pounds of compression on both sides, dead even from side to side. Sounds MUCH stronger now, smooth running, still loud but smooth.

SO moral of the story : check everything before you start fixing things. I should have just pulled the valve covers and heads off both sides and checked it all out and could have fixed i tt he first time,but oh well, its all good now.

THnaks again to everyone for their help, and duane for the pictures and all the help.


DOUG

[duaneb55]

Job well done Doug. :drinkup:

20/20 vision is always the case after navigating unfamiliar territory. No doubt you have a much better understanding of the machine than when you started which is definitely a good thing.

If the valves weren't waaaaaay out of adjustment (loose) when you first put it back together, my guess would be overspeed causing valve float was the cause of failure but it's just a guess.

[Horvik]

Hey Duane;

My 2 cents is sounds like it was low on oil and pushed hard to make her stick like that. Heard Onans come down with this kinda headache. I been lucky with that old 16 HP cast iron Briggs Single on my Weldanpower 225. Welds as long as you can stand!

all the best
. Job well done Doug. :drinkup:

20/20 vision is always the case after navigating unfamiliar territory. No doubt you have a much better understanding of the machine than when you started which is definitely a good thing.

If the valves weren't waaaaaay out of adjustment (loose) when you first put it back together, my guess would be overspeed causing valve float was the cause of failure but it's just a guess.

[freshintulsa]

Little follow up on this project. I've put a few hours on the machine now. Welds great, tigs great, runs great. One minor issue, it seems to have a very high low idle. Im not too sure on how to adjust or check actual RPMs. Anyone have some ideas on what to check? I dont know if I need to adjust the carburator or something else. At the start of this project, I did put on a new carburator. It doesn't seem to really change from low idle to high idle. It might just be my head, but I do believe it does change, but very slightly. I could be wrong, maybe its just stuck in high idle.
So, is there something I should check for adjustment?

Thanks again, Doug

[freshintulsa]

Any ideas?

[freshintulsa]

I dont know if anyone is interested to know, but I got the low idle back to normal. I'm not sure if this is the right way to fix this or not, but it worked.

I took off the top cover and located the idle solenoid. There is a spring on one side of the throttle cable, and a nut on the other. I tightened the nut, bringing the throttle closer to the solenoid and lowering the idle.

Again, I dont know if this is the proper way to adjust the low idle, but I tried everything except adjusting the carburetor.


Hope this helps someone in the future.


Doug

[Bluewelders]

The valve stems getting a thin film of varnish or rust will stick a little,the valve does not follow the cam and the extra gap lets the cap fall off of the valve.
If they stick enough the piston wacks the valve.
Briggs some years ago, had the pivot stud on their OHV engines backing out, and that caused the same loss of compression.
Lots of lawn tractors thrown away,that just needed some loctite on the replaced stud.