Gravely Onan Question

9131 Views 36 Replies 10 Participants Last post by Richard-tx, Nov 10, 2010

Jimmy in NC

Discussion Starter · Nov 4, 2010

So I stumbled onto a 8000 series rider for sale local that has an Onan 18 hp on it (supposedly). Going to look at it tomorrow but as I'm not very familiar with Onans; what should I look for? I know the usual, clutches, spindles, etc. but the Onan is the part that makes me wonder as they can quickly be expensive I hear.

Do these motors have points? Should I take time to pull a compression check on both cylinders? Are the plugs easy to access?? Any quick tip offs to watch for? I do not need a maintenance heavy machine. This is to avoid the re-sleeve and rebuild of my 816S if possible. I'm close to the same price for this tractor or the parts and machine work for the rebuild.

Only 'known' issue is the PTO is acting "funny." He says it will disengage if you hold the lever disengaged but as soon as you let off it comes back in. Lining come unglued?? If the PTO clutch is funky... price better come down a bit; I've been into the tranny of the 816 and I'm not against it but I also know those things are real expensive new and not cheap used.

Sorry for the long post, but figured better to ask questions before as opposed to after.

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1 - 20 of 37 Posts

Fla Don

· #2 · Nov 5, 2010

The 18 HP Onans are B48M-GA018 engines. They have points unless someone spent the money to upgade to electronic ignition. That's what killed the B48M-GA019 19 HP at the shop. Upgrade is $1000 which is ~ half the price of a Kohler Command Pro 18. Plugs are easy to get to. PSI reading should be 90 or better with oil in the cylinder. Intake manifold failure is something to watch for as the joint between halves can breakdown. Sounds like the linkage isn't adjusted right.

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Hugh-SS/16

· #3 · Nov 5, 2010

i cant tell you what to look for on the tractor, but i know what to look for on the onan.

besides the usual things like easy starting, smooth running, etc, look for the condition of the air cleaner, surging while running, and fuel pump strength

arcam8123

· #4 · Nov 5, 2010

Depends on the asking price. If it's a lot, check the compression and the PTO. I think the parts for the pto is around $400 bucks.

Richard-tx

· #5 · Nov 5, 2010 (Edited)

If it were me, I would not worry about the points and condenser unless it was running poorly or not at all. I would not worry about the compression either unless there was an issue. When you get it running, the smoke or lack of smoke in the exhaust would tell you what the condition of the rings are.

Points and condenser isn't hard to change. You just need the right tools.

Onan engines are a premium engine and they will last a long time if you take care of them.

Most of the time, when I see a poor running Onan, it is usually due to some dirt of crud in the carb. Occassionally I will see a bad coil on the 16 HP Onan engines, but a bad coil is pretty obvious.

I have found the Onan engines reliable, smooth, and powerful.

To me a Gravely 4 wheeler isn't a Gravely unless it has an Onan or other two cylinder engine on it.

PTO clutch and rear wheel hubs are both potential issues no matter what engine is on the tractor.

Fwd and reverse clutches are so easy to service that they are of no concern to me. The exception would be damaged or worn out shafts.

I have a 818T and would lot trade it for anything...well maybe a Onan 24.

What Don said....the PTO linkage needs to be adjusted. Have your torch handy.

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Code:

                              [U]Current Inventory[/U]
   24G (Onan 24hp)    24GLX - was 16G  (Onan 24hp)   8249 - was 8129 (Onan 24hp)
        818T (Onan 18hp B48)       8163T - was 8123 (Onan CCKA) 
                              8183T (Onan B48)
   5665 w/brakes        5665        5660        Pro-8         Pro-16 w/brakes

For Gravely Manuals and more visit [url]http://GTCOA.com[/url]

Jimmy in NC

Discussion Starter · #6 · Nov 5, 2010

I'll know when I see it. The big thing is I don't need another major project. I'm burning half a quart of oil a week in the big single Briggs right now and it eats an air filter in 2-3 weeks. I'm hoping to get something that the drive train is fine on and if the deck is less than stellar, pop my 50" under and keep getting it. I just don't have time to sleeve and rebuild the 16. I will keep it and do it in the future.

As for points, I was really just curious. I run many things with them and don't mind them, just prefer breaker-less. I know the Onans sound sweet and we'll see. Probably go look at it tonight, smoke it over this evening, and if it is what I want, pick it up Sat. AM. Either way I'll get pictures for all the picture lovers around here.

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Fla Don

· #7 · Nov 5, 2010

Richard-tx said:
If it were me, I would not worry about the points and condenser unless it was running poorly or not at all. I would not worry about the compression either unless there was an issue. When you get it running, the smoke or lack of smoke in the exhaust would tell you what the condition of the rings are.

Points and condenser isn't hard to change. You just need the right tools.

Onan engines are a premium engine and they will last a long time if you take care of them.

Most of the time, when I see a poor running Onan, it is usually due to some dirt of crud in the carb. Occassionally I will see a bad coil on the 16 HP Onan engines, but a bad coil is pretty obvious.

I have found the Onan engines reliable, smooth, and powerful.

To me a Gravely 4 wheeler isn't a Gravely unless it has an Onan or other two cylinder engine on it.

PTO clutch and rear wheel hubs are both potential issues no matter what engine is on the tractor.

Fwd and reverse clutches are so easy to service that they are of no concern to me. The exception would be damaged or worn out shafts.

I have a 818T and would lot trade it for anything...well maybe a Onan 24.

What Don said....the PTO linkage needs to be adjusted. Have your torch handy.

We see coils fail on them down here due to the heat and humidity. Same thing as happens with the Kohler KT series coils. Points here can fail in a week as we go from hot to cold to hot every day with our rain storms. A day with the humidity below 85% is a dry day.

I love the Onan twins for the reasons you stated.:trink39: We've owned one since 1981 and we currently have 5. Two of the tractors are 2 serial numbers apart. And soon to have an Onan single too.

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Jimmy in NC

Discussion Starter · #8 · Nov 7, 2010

Well.. I'm into Onan's now. Came home with an 8183-T today. Best I can figure, 1980 model. Shows ~ 400 hrs and the tractor looks it. Hour meter still works. Cranks good, runs fairly well... think the carb needs going through. The previous owner was using it as a bush hog that his son could drive "mowing waist high grass in high gear." Needless to say it needs a PTO clutch. It runs if you bear down on the PTO lever... HARD.

Will post pics tomorrow but the camera batteries died tonight taking pic #3.

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arcam8123

· #9 · Nov 7, 2010

When you say it looks like it has 400 hours on it, I assuming it looks real good! 400 hours on an Onan is bearly broken in.

Jimmy in NC

Discussion Starter · #10 · Nov 7, 2010

Yeah... faded, muffler guards are a tad beat, but over all in great shape. Just a bunch of sitting on the poor old girl. Don't worry.. I'm going to put it back to work.

Mickeymotormount

· #11 · Nov 7, 2010

Nice find Jimmy. That ol' girl's in good hands now. I'm sure you'll have her working in no time. Good luck.

Jimmy in NC

Discussion Starter · #12 · Nov 7, 2010

Pics from last night:

More to come later today.

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Jimmy in NC

Discussion Starter · #13 · Nov 8, 2010

Well I got some more pictures this AM and finally got 5 minutes to look it over in sunlight with out rain drops. Overall it's very solid and had lots of potential. 95% of the damage on it has occurred from sitting out side. Clutches are in good shape, deck is real straight and will only require minor rework of the front edge, rear fender is straight. Will need the PTO clutch replaced and probably a carb rebuild for good measure. Be a fun project and I look forward to more power than the worn out single I've been running.

I have the missing exhaust guard and missing turn out.

Clutches have lots of life left in them.

Glad I have another hood in the barn that isn't mutilated!

Working hour meter... shows just over 400 hrs.

Being hauled across the yard to start the nursing back to health.

And there are a few more pics here:
http://s2.photobucket.com/albums/y49/NCSU4x4/Gravely 8183-T/

Sorry they are big.. but it's more fun to get a good view and I'm sure some of you will point out what's wrong with it... let me know! I want to get it right now instead of when it fails!

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yamato72

· #14 · Nov 8, 2010

In a word: "Wunnerful!" Keep the pics coming!

tracktortag

· #15 · Nov 8, 2010

Nice find. It looks like it very good condition. Nice to see your 81X too.

coldone

· #16 · Nov 8, 2010

Very nice. Looking forward to the resto

Mickeymotormount

· #17 · Nov 8, 2010

Lots of potential Jim. Good luck with the pto installation. Your pics of the inside of the trans helped me with replacing one I had so I know you're a seasoned veteran.
I like the Onan. Makes me wonder if the newer style Onan P216,218 or 220 series engine could be bolted up to the tractor. I have a 16G needing an engine. Hmmmmmmmmm..............

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Jimmy in NC

Discussion Starter · #18 · Nov 8, 2010

First step is to get the carb cleaned and get it back to running proper. The PO mentioned he got to messing with the carb and it was never right after that. I'll go through it for good measure, check the float since he said it was flooding when parked, etc. We'll go from there. I'll get plenty of pictures since I know everyone likes them and it also helps me to remeber where I came from on these projects.

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Fla Don

· #19 · Nov 8, 2010

Mickeymotormount said:
Lots of potential Jim. Good luck with the pto installation. Your pics of the inside of the trans helped me with replacing one I had so I know you're a seasoned veteran.
I like the Onan. Makes me wonder if the newer style Onan P216,218 or 220 series engine could be bolted up to the tractor. I have a 16G needing an engine. Hmmmmmmmmm..............

P-224 on the 24-G models. Just about any engine can be bolted on if you make the proper adapters. Still thinking about a 40 HP Kohler just for the fun of it.
But I hate the idea of taking an engine apart just to change the crankshaft when new.

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Richard-tx

· #20 · Nov 8, 2010

I am a bit leery of overdoing the horsepower. I remember years ago one fellow that took a Ford Pinto and put a small block V-8 in it. After he added bigger tires, the differential exploded. After he put in a bigger diff, then the frame broke. In short, there are certain design limits that need to be taken into consideration. He should have taken a Mustang and put a custom Pinto body on it;He would have been money ahead.

Keeping the power down to something reasonable will help prevent certain things from happening like in the pictures below.

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Code:

                              [U]Current Inventory[/U]
   24G (Onan 24hp)    24GLX - was 16G  (Onan 24hp)   8249 - was 8129 (Onan 24hp)
        818T (Onan 18hp B48)       8163T - was 8123 (Onan CCKA) 
                              8183T (Onan B48)
   5665 w/brakes        5665        5660        Pro-8         Pro-16 w/brakes

For Gravely Manuals and more visit [url]http://GTCOA.com[/url]

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