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9 HP Portable Otto Gas Engine Mechanical Restoration

Chris Epping

Subscriber
Age
36
Last Subscription Date
07/09/2019
I’ve been meaning to start a restoration thread on this engine for the past couple months, but am just now getting around to it. Last summer we brought this engine home in complete, but well used condition. The “bones” of the engine were good, but it had a lot of battle scars and wear that needed attention. I believe the story on it was that it originally came from a farm in New York State. I’m still gathering the history on it and will correct this if it is not accurate. Besides being worn, the engine had some “amateur repairs” made to it at some time in the past 100 years, which as usual, made the problems worse rather than better.

I have always liked Otto engines and, while some collectors would say they aren’t that super rare or unique, when I’m pondering on one I am always compelled to give homage to the company and the name that revolutionized the world with the first successful 4-cycle engine. I suppose there are hundreds of Otto engines around the USA and the world, but this factory portable is quite an odd specimen with only just a few left in existence. The first reason for this would likely be the original low production numbers for portable farm use. The company primarily produced engines for mill and industrial work, and few farms of the 1900 era would have sprung for a engine of this quality and cost. As I stated in an earlier thread on this same subject, one of my reasons for wanting to bring an original factory portable home was a family connection that was discovered when my sister was searching through photos from her family’s farm at Broken Bow Nebraska and discovered they had a portable Otto there at one time. So, when I got a chance to bring one home, it just seemed like the thing to do!


The engine itself is a standard Otto Gasoline engine, like most others we all have seen. The unique portable features start with a cart of extremely high quality and heavy build. Castings between the frame rails secure the engine to the cart, the oversize wheels are generously spoked, and the axles are heavily built and braced making for a top notch transport. The cart is even equipped with a factory foot brake. The cooling system is also very unique with a sheet metal tank attached on top of the cylinder. There is a forge blower attached to the side of the cart rail that is belt driven off the rim of the flywheel. This blower pushes air through a pipe in the center of the tank which is meant to cool the water coming out of the top of the cylinder. Other features include an operators seat, tool/battery box, and a clutch pulley for portable belt work. There was a lot of attention to detail in every aspect of this design and build with many hand forged and proprietary parts and features.


Following that bit of background, I will try to chronicle the restoration work as it goes along. Unfortunately I didn’t take as many pictures as I should have, so you will be spared some of the lesser details, but I have a number of progress photos that I will try to share in the coming days. Thanks for viewing!
A3857B7C-C081-4060-A186-E51AFD914401.jpegD9B6AFB0-6860-44C8-A7F3-CEE075A8F3E3.jpegB41B9164-955D-469A-8A91-2612E99CF2EA.jpegE05BD10F-0AC5-4FE7-BE63-226332C6A2A1.jpeg59B289B0-F9D5-4BAD-8E1F-6A439A6A978A.jpeg
Following that bit of background, I will try to chronicle the restoration work as it goes along. Unfortunately I didn’t take as many pictures as I should have, so you will be spared some of the lesser details, but I have a number of progress photos that I will try to share in the coming days. Thanks for viewing!
 
Last edited:

LCJudge

Subscriber
Age
60
Last Subscription Date
12/14/2019
Yes Chris, the engine came from New York. I don't remember all the details but remember going and picking it up (and getting stopped by the town police while there). I have a photo of it here when it was in the shed i NY. I think the guy who had owned it (I bought it from the family) had taken it to a show(s) in the past. Ed can possibly provide info since that's in his neck of the woods. I do have some photos of it here (somewhere) of it when I got it. A friend in NC told me about the engine and that it was going to be sold.
 

Chris Epping

Subscriber
Age
36
Last Subscription Date
07/09/2019
Chris, do you think the engine would have been a standard tank cooled 'most parts inter changeable' engine that was factory adapted for a portable?
Gene, good question. I expect the engine itself is the same as most other engines of this size and style, but I don’t have another 8-10 HP to compare to, so I don’t know for certain.

Here are some more pictures of the initial tear down. The engine appeared to have had something similar to a liquid grease poured on it. I expect in an attempt to preserve it, but if nothing else it made quite a mess to clean off! Check out the head studs and what happens to steel that is submersed in cooling water for many years.5625D835-F3AB-4593-A37F-306E9535E38B.jpeg804C70A0-136C-45C1-8C14-D352B290FA51.jpegCD203074-18FD-4301-9036-FBC15799BC9B.jpeg390D3C5C-B2C9-4BEC-BA4B-1E10998F73B4.jpegF1CB0A46-2F70-4DE0-BE37-F2EDD1AD1278.jpegC93DC234-17A0-429F-B390-62FDC3ACC179.jpeg
 

Gene Fisher

Sponsor
Age
81
Last Subscription Date
11/22/2019
As Witte and some others did not put the head bolts through the casting but in the water passages which was a poor design. You would think those manufacturers of quality engines would have known better. Yes the engines are over 100 years old but the rust started soon after it was first used. Many others did not use this method of head bolting and the bolts are still good.
 

Dave Nielsen

Registered
Last Subscription Date
02/07/2018
I believe this engine was shown at the Canandaigua around 10 years ago. I help unloaded the engine at the show. It was the only portable Otto I ever seen. Dave
 

Chris Epping

Subscriber
Age
36
Last Subscription Date
07/09/2019
As Witte and some others did not put the head bolts through the casting but in the water passages which was a poor design. You would think those manufacturers of quality engines would have known better. Yes the engines are over 100 years old but the rust started soon after it was first used. Many others did not use this method of head bolting and the bolts are still good.
You are very correct Gene, you would think they would have thought better of that idea, but there were a number of companies that built engines this way. It was pretty much a full day project to get the head off. We purposely twisted the studs off but then the head was still very much stuck on the remaining studs. Also the valve cages in the side of the head were very stuck in place. The fuel valve came out easier than the intake valve did. I had to gently heat, tap, and twist on it to break the 100+ year carbon and rust bond. These cages are quite delicate so extra time and care was worth it to not have to repair or replace parts later. These pieces came out finally, and after inspection we found a lot of work to do:

The exhaust valve cage was eaten up from the inside out. There’s not much left holding the part of the casting where the exhaust pipe screws in. The pipe threads are completely gone. And there is a 1 1/2” dia hole in the side that has been plugged with a bolt and a washer. Not sure if this part is repairable or if a new one will have to be cast.....

The head has been frost broken once, poorly repaired, and frost broken once again. The entire bottom is coming out of the head and there is also a freeze crack on top. And to top it off, one of the igniter studs has been knocked out at some point and the boss around it is broken out. The head will have to be repaired, not much other choice on it....

And finally, the water jacket (which is a cast tube separate from the cylinder) is split from one end to the other. Either someone tried to grind on it at some point to attempt to weld it, or the crack exposed the material to further decay, but it is quite thin at the point of the damage.....

So I have many days of work here and I’ve only just begun to disassemble!
 

Chris Epping

Subscriber
Age
36
Last Subscription Date
07/09/2019
Chris,
what diameter did those head studs start there life out as ? They ended up looking like some ornamental wrought iron.
They were originally 5/8 inch studs, but were down to 5/16 in places! Yes, I thought the same thing, after I twisted them about six times before they broke, they looked like they could have been in a wrought iron fence! They must have been pretty soft to twist that much prior to breaking.

The amazing part was that with some well placed heat and a good pipe wrench, I was able to remove all of the studs with drilling any out. To remove the cylinder I had to torch off the remains of the nuts as there was no chance of getting them off otherwise. Once again, more studs to replace.B109F12F-8AFF-4758-99F8-6D47BA009094.jpeg86765D9C-66E1-46E5-AFCC-6A57B65813A3.jpeg38F79AF9-2B9A-4432-9502-3935CF5744C7.jpegAACD32BA-F0CD-4528-B62E-A54440670F5D.jpeg
 
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Kevin O. Pulver

Email NOT Working
Age
54
Last Subscription Date
02/14/2020
Chris, for some reason I think this is about the coolest engine you've ever shown.
Part of it is the funny tin water Hopper and the forge blower for extra Cooling.
And as you said that cart is really neat with all those castings on it.
Also I love the connection that your brother-in-law had one on their Broken Bow Nebraska Farm back in the day. There couldn't have been more than about one of these engines on a Nebraska Farm could there? How neat that they have a picture. I'm sure you have a copy made already but you'll need a large framed one to display near the engine!
Thanks for taking the time to document this and share it with us!
 

Chris Epping

Subscriber
Age
36
Last Subscription Date
07/09/2019
Chris, for some reason I think this is about the coolest engine you've ever shown.
Part of it is the funny tin water Hopper and the forge blower for extra Cooling.
And as you said that cart is really neat with all those castings on it.
Also I love the connection that your brother-in-law had one on their Broken Bow Nebraska Farm back in the day. There couldn't have been more than about one of these engines on a Nebraska Farm could there? How neat that they have a picture. I'm sure you have a copy made already but you'll need a large framed one to display near the engine!
Thanks for taking the time to document this and share it with us!
Thanks for the comments Kevin, and yes I agree on all points. There were quite a few Otto engines in Nebraska at one time, we got three of them out of grain elevators, but I would guess most of them were confined to commercial or municipal uses. Many of the farms out here would have spent the money on a tractor rather than a portable gas engine. Or if they did buy a quality engine, it would have likely been an IHC famous or N Fairbanks. There must have been a good Otto salesman here though, as about every town along our rail line had an Otto in it. And they must have made their way up north as well when they sold the Otto portable to their farm, and they also sold an early hopper cooled Otto to the National Forrest project at Halsey NE. That engine happened to survive. I've posted these pictures from the family album before, but will post them again in case some didn't see them the first time.
 

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Kevin O. Pulver

Email NOT Working
Age
54
Last Subscription Date
02/14/2020
This is a good place to post those pictures again Chris. I think I remember you posted them before and I asked you if the barn was still there, and you said it was not. Otherwise it would have been neat to get a picture of this thing beside the old barn.
 

Chris Epping

Subscriber
Age
36
Last Subscription Date
07/09/2019
I did a poor job of documenting this first weld repair, so I apologize for that. I think I had my doubts if I could fix it, so I believe that was why I didn’t take any good “before pictures, but this exhaust valve box had no threads left inside and a hole about 1 1/4 in diameter in the side from rot out burnt exhaust soot and acids. A bolt and washer had been put in the hole to plug it, and the pipe fell apart when I put a wrench on it. With nothing to lose, I cleaned it up as best I could. Built a small furnace for it, and got to cast welding on it with a torch. With the entire casting slowly preheated to a dull red, I built up the area inside the pipe thread outlet almost 3/8 of an inch all the way around. I also filled the hole in the side and left enough weld inside to restore the strength of the casting. After the weld job was successfully completed, the box was setup in the mill and faced off on the sealing surface. The exhaust outlet is also bored and threaded back to the original NPT connection. The valve guide is also bored and sleeved and a new valve built with a cast iron head and steel stem. After a few days work, the original piece is saved. Although still weathered looking, it is mechanically renewed and original to the engine! One piece down, a bunch more to go....47D31DC2-C339-4CFC-9F91-44B00AA2CDD5.png852FF767-D32C-4F50-BE0A-7B9ADDB49C36.jpeg62555200-B56C-4EC5-9F1A-F73A5C8C5F90.jpeg113CDAC8-B47A-475A-85B7-E432E3D6A512.jpegA9CA1BF1-7F75-4CD8-BC53-B4A554755DBF.png
 

Kevin Roth

Subscriber
Last Subscription Date
02/08/2020
Chris, I am sure enjoying your posts on your restoration projects. You are getting good with your welding and machine work you are doing. With a little patience and practice cast welding with a torch isn't that hard to do. Keep up the good work and stay safe.
 

Chris Epping

Subscriber
Age
36
Last Subscription Date
07/09/2019
Chris, I am sure enjoying your posts on your restoration projects. You are getting good with your welding and machine work you are doing. With a little patience and practice cast welding with a torch isn't that hard to do. Keep up the good work and stay safe.
Thanks for your comments Kevin. I've done a fair bit of cast welding, for some reason some irons weld better than others. As burned out as areas of this casting were I was surprised it turned out as well as it did. The heating is cooling is critical.
 

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