I just replaced a tired and aging HSK70 7HP "snow king" Tecumseh. I found a high value NOS 11 HP OH318EA-222712. 115 USD with 30 dollar ship. Seems there are a bunch of these with a 7/8" tapered shaft that have no application beyond a certain Coleman generator. Good deal for me since I have a full shop with lathe and tig welder. I just bored the pulley ID to match the shaft and put two tig spots on the end to secure it. Future tear down? Just grind off the two small tig spots.
No matter how I work to tune it the new engine wants to hunt. The OH318EA is not a dedicated "winter" engine. Can anyone help me determine what needs to be tweaked to make it so? It does have a reversible filter cover that either draws from the side or, rotated 180 degrees (in winter mode), draws from a shroud around the muffler. I removed the paper filter which itself might account for leaning the mix a bit more than was designed for.
So it is winterized to the best I'm able. But no matter what I do, and I'm generally confident in my small engine tuning skills, it wants to "hunt". The OH318EA is a single speed motor. I have a digital tachometer so I can spot it at 3600 rpm after getting all else tuned. There are five notches on the arm that attaches to the governor output shaft. I've worked with all five of them. The only other adjustment on this engine is a 3/8 nut that puts more/less tension on the spring attached to those five notches. I've seen this engine listed, at this price, online now for over five years. It may be that the carb gets varnished on the shelf. Running it and spraying carb cleaner into the high speed circuit did not seem to help. I may need to disassemble and completely clean the carb. There are zero adjustments on this carb.
In all possible combinations I cannot get it to stay smooth without it hunting when the snow gets deep and taxes the engine. After about 60 seconds of driving through heavy snow it starts to hunt again and eventually will just die. Frustrating.
There are no other adjustments on this motor. I'm wondering however if I might ream out the main jet/emulsion tube (have not looked yet so I don't know if they are separate) ever so slightly and work upward from there. I have many micro drills in a wide range of sizes/gauges. Supposedly this OHV engine is tuned very lean to meet emissions standards. As a generator duty motor it may not have been set up for high load minutes at a time. Perhaps I need to start with a richer (ever so slightly reamed) main jet?
Thanks for any advice you can give. When it is running it's a real joy. The 30 year old HSK70 was probably only 5hp after all these years. A fresh 11hp OHV really sends the snow over the trees and, when not eventually hunting, cuts through tall wet snow without losing any rpm at all. The HSK70 used to drop about 30 percent or more and just chug and strain through the deep stuff. It kept going, but really slowed down the job.
No matter how I work to tune it the new engine wants to hunt. The OH318EA is not a dedicated "winter" engine. Can anyone help me determine what needs to be tweaked to make it so? It does have a reversible filter cover that either draws from the side or, rotated 180 degrees (in winter mode), draws from a shroud around the muffler. I removed the paper filter which itself might account for leaning the mix a bit more than was designed for.
So it is winterized to the best I'm able. But no matter what I do, and I'm generally confident in my small engine tuning skills, it wants to "hunt". The OH318EA is a single speed motor. I have a digital tachometer so I can spot it at 3600 rpm after getting all else tuned. There are five notches on the arm that attaches to the governor output shaft. I've worked with all five of them. The only other adjustment on this engine is a 3/8 nut that puts more/less tension on the spring attached to those five notches. I've seen this engine listed, at this price, online now for over five years. It may be that the carb gets varnished on the shelf. Running it and spraying carb cleaner into the high speed circuit did not seem to help. I may need to disassemble and completely clean the carb. There are zero adjustments on this carb.
In all possible combinations I cannot get it to stay smooth without it hunting when the snow gets deep and taxes the engine. After about 60 seconds of driving through heavy snow it starts to hunt again and eventually will just die. Frustrating.
There are no other adjustments on this motor. I'm wondering however if I might ream out the main jet/emulsion tube (have not looked yet so I don't know if they are separate) ever so slightly and work upward from there. I have many micro drills in a wide range of sizes/gauges. Supposedly this OHV engine is tuned very lean to meet emissions standards. As a generator duty motor it may not have been set up for high load minutes at a time. Perhaps I need to start with a richer (ever so slightly reamed) main jet?
Thanks for any advice you can give. When it is running it's a real joy. The 30 year old HSK70 was probably only 5hp after all these years. A fresh 11hp OHV really sends the snow over the trees and, when not eventually hunting, cuts through tall wet snow without losing any rpm at all. The HSK70 used to drop about 30 percent or more and just chug and strain through the deep stuff. It kept going, but really slowed down the job.
