[29 Chev]

That looks like a heavy duty splitter for sure - thanks for sharing the pictures. Will offer you a suggestion for an oil drain area - hope you don't mind. Could cut about an inch wide slot from the outer edge of the U channel to about half an inch in past the edge of the engine - drill a hole at the inner end to give it a nice round look. After you mount the engine put a bead of RTV between the engine edge and the U channel so oil cannot flow in under the engine. Don't think the slot would weaken things much and then you could slide a small tray in the opening to catch the oil - just a suggestion.

Keep us posted on the upgrade as it is good information to share your experience with the new engine and how it performs.

 

[29 Chev]

I noticed that the motor has a Torch brand spark plug in it. Had one of those fail in a portable generator after about 30 hours of use. Must have burned out internally, wouldn't spark at all. I replaced it with a Champion and have had no issues since. I saw in the Predator owners manual that NGK brand spark plug was listed along with Torch as replacements. I know that Champion and Autolite plugs cross reference too. I stopped at the auto parts store today and bought a NGK plug. I figure I'll just put the new plug it just because. I took a look at the box the plug came in and NGK is a Japanese company, I seem to remember that fact from buying NGK plugs in the past. Plug was assembled in Thailand also printed on the box. Now I'm starting to wonder about the quality. I guess I'll find out. I know that is possible to buy a bad spark plug no matter what brand. Have had it happen. Maybe I'm over-thinking things again?

I have been using NGK plugs in the Honda GX390 ever since I installed the engine and have good luck with them - just my experience with the NGK brand. As you say any brand can fail and I have had it happen - like everything else made by man - prone to failure. About 5 years ago I was having a problem with what I thought was a NGK spark plug issue where they appeared to go bad and misfiring as I was replacing the plug about every 10 hours. First one I thought got a dud, second one made me think that NGK brand was not as good as it once was. When the third one failed I called the NGK tech line and described the scenario to the gentleman on the other end of the phone and asked if they were having problems with the part number I was using. The gentleman said no and politely told me that the mixture was too rich and that the plug was becoming wet fouled and not able to burn off the extra fuel causing it to fail after about 10 hours of use. I thanked him and hung up the phone thinking that the gentleman did not know poop from putty as the Honda GX390 main jet is fixed. His words of wisdom stuck in the back of my mind though as I thought about an intermittent coil or bad plug wire causing the issue (ordered new ones of each to have on hand for the next time the plug failed) but it turned out he was correct. I was using the tractor one morning shortly afterwards while it was still dark and after about 10 minutes use blowing snow I could see the short piece of exhaust pipe between the engine and the muffler was glowing a faint shade of red. I thought to myself why would the exhaust pipe be glowing red as it never used to do that before - decided that maybe the gentleman at NGK knew more than I thought he did. Removed the homemade shield that covered the carb which revealed the idle mixture screw which is not fixed but does have a limiter cap. Upon further investigation I discovered that somehow the idle mixture screw had moved outward as far as it could travel with the limiter cap on which was up against the carb body. Turned the screw in until the limit cap stop was up against the carb body and put the shield back on and waited for the next snowfall which occurred a few days later. I purposely got up before daylight and started the tractor up and got busy removing snow while observing the exhaust pipe. Used the tractor for a good 20 minutes in the darkness and the exhaust pipe stayed dark this time and I have not had an issue with the spark plug failing since. As near as I can tell with the idle screw open slightly more it allowed excess fuel to be drawn into the intake through the idle circuit which was creating a rich mixture at wide open throttle and by turning the screw back in the fuel mixture returned to the proper amount of fuel being delivered. I would not have believed it if I had not experienced it and in my mind I apologized for thinking that the NGK tech didn't know poop from putty - as it turned out he was much wiser than I was when it came to fuel mixture and spark plug problems.
Not saying you won't have an NGK plug fail but I would say the odds are against it or if it does it may not be all the plugs fault. I apologize for the long post but thought I would share my experience with NGK and their tech department.

 

[29 Chev]

Stew, I’ve never heard of a exhaust pipe getting orange/red with a rich mixture. Always thought when it was a lean mixture that it could do that. Interesting.

Noel

I assume that what was happening was that with the rich fuel mixture all the fuel was not able to burn in the combustion chamber due to a lack of oxygen that was used up with the normal amount of fuel. Once the non spent fuel left the combustion area through the exhaust valve and encountered fresh air from outside present inside the muffler the hot fuel would self ignite inside the exhaust pipe where normally there would just be spent exhaust gasses - just my thoughts. Would think it would be like having a small torch heating up the inside of the pipe with the excess fuel being ignited as it entered the inlet to the exhaust pipe. Would think a lean mixture would burn up all the fuel inside the combustion area since there would be an abundance of air to fuel resulting in just spent exhaust gasses in the exhaust pipe - just my thoughts.