• If you like antique engines, vintage tractors or old iron, please register and join us. When registering, please provide your CITY and STATE as your location!

Ohlsson & Rice 1hp Type 115


Hello All,
I recently purchased an old Ohlsson & Rice 1hp engine, waiting for delivery next week. It is missing the spark plug and a gas tank. I’m also expecting that the carburetor will need to be completely overhauled and a new diaphragm and gasket needed. I’ve done a little research and it appears this is a common problem and parts are obviously no longer available. Does anyone have any recommendations for alternate approaches or materials that can be used to make a diaphragm? Also, what is the recommended spark plug for these engines? Mine is stamped Type 115 and the serial number looks to be an early model. The carburetor on this one is different from nearly all other O&R ngines ive seen. Most have a small spring loaded primer button in the center of the top plate and mine isn’t completely flat with no button.

I look forward to your expert advice!


In Memory Of
Last Subscription Date
Think the plug is maybe a CM6, or CMR6A for resistor type. Smallest commercial plug I know of.


If the carburetor on your O&R does not have a centrally mounted primer button, chances are that the carburetor is the older style with the stainless steel inlet needle (ball bearing). These carburetors are much more reliable than the later style with the rubber inlet needle. I have put old diaphragms in warm water for several hours to make them plyable for reuse. Do not put these old diaphragms in an ultrasonic cleaner. It will blast holes in the diaphragm and make it unusable. The best method for getting an O&R running with no primer is to put the choke on half way, and hookup a rubber tipped air blow gun to the fuel tank. Surround the tip of the blowgun with some paper towels so that when you let off pressur eyou do not get covered in fuel. With a clear/tygon fuel line, go real slow on air pressure, only about 5psi is needed. Watch the fuel push through the tube until it reaches the carburetor. Pull the spark plug and crank the engine a few times to be sure it hasn't hydrolocked. Then choke the engine and it will run. If you do not do this you will pull and pull until the recoil breaks.



Doc & Chris,
Thank you for the quick replies and excellent advice. I’m anxious to confirm the carburetor style once it arrives. It would be great if I have one of the more robust versions. I appreciate the recommendation for th spark plug and will explore that further. Also the tip on priming it is great, I would never have thought of that one!

I should have also asked, what is the consensus on recommended oil/gas ratio or use of a quality premix fuel?

Thanks again!

Mike in NC

Last Subscription Date
According to one manual, the mixture is 24:1 and another manual says 16:1. Use SAE 30W oil.