I am looking for some guidance re a problem with my Zenoah G45. I ran the engine last year in a Midwest Extra but moved the engine to a Stinger 120 for this season. Right off the bat I am having troubles with the engine. It has a CH Jump Start ignition that worked like a charm last year. The problem is that I can start the engine with the jump start - no problem. But when I switch the jump start switch position from 'start' to 'run' the engine picks up rpm's for about 2-3 seconds (like it used to when it ran fine) but then it starts to run very rough and bogs if I try to increase the throttle. It won't pick up speed, just runs real rough. Usually it seems to hang in for about 5-10 more seconds then just quits. At first I thought I had the butterfly (throttle plate) rigged backwards, but I have checked that and I have it installed the right way around.

I need some guidance in how to trouble shoot this. My thoughts are that there is a problem in the ignition but I don't know whether it is in the jump start circuitry or the magneto. It almost seems like the timing is off. If I understand correctly the jump start basically retards the ignition to prevent backfire etc. In the situation I have described, when I start the engine and then flip the switch to run, it is alomost like there is no proper throttle response. Moving the throttle stick up just seems to bog the engine down.

I checked the carb - took it off - cleaned the screen, took out the needles and blew all passages, also took the float needle out and checked that it was clear. I can find no problems with the carb. I seem to be getting lots of gas to the carb, and I have it wet before trying to start it. Seems more like an ignition / timing problem.

To check out the jump start I have followed the suggestions in the instructions. If I take the plug out and ground it while flipping the prop I get a good spark with the jump start battery pack plugged in. Also if I check the voltage on the middle pin of the Deans connector I get well over 6 volts, so that seems fine. Not sure what else I should do to check the integrity of the Jump Start circuitry.

Any and all suggestions would be welcome.

Bill

Unwire th jump start. Try running the engine without it. I had a jump start my on 45, but found it starts fine with out it.

Sounds like the jump start is causing the ignition timing to stay fully retarded. I would do what cabane said and try running it without the jumpstart. My G38 starts fine just by slapping the prop. I think the key is to close the choke and open the throttle and flip the prop 5-6 times. Then slap it till it pops. Then open the choke close the throttle and slap the prop again. Should fire up within 2-4 slaps. Hope this helps.

Hi guys - sorry for the delay in responding. Had to go out of town on business for 3 days. I started to have a closer look at the jump start tonight and found that the switch is broken and malfunctioning. In fact the toggle came apart in my hand. I think I was getting an intermittent connection back to the jump start even after I thought the switch was flipped from start to run. I ran out and bought a new switch and wired it in. However, it is dark now and we will have to wait for suitable weather tomorrow to give it a test run. I will post the results of putting in the new switch

Thanks for the replies.

Bill

New switch did the trick - we are off to the races now. Runs fine - problem solved

Bill

Maybe the type of toggle switch you were using could not handle the vibrations caused by your engine. Changing to a simple Rx switch harness that is designed to handle vibrations might be a better solution in the long run. Just my 2 cents.

karolh - that is a very good thought. I basically replaced the toggle that came with the jump start with essentially the same type of toggle. But if it fails again in the near future I will need to consider another option such as what you just provided. Thanks for the idea !

Bill

billpilotca, How is the performance with the G45 in the 120 stinger, and what prop are you turning. I am running a us41 in my 120 stinger. I am now getting pretty good performance after changing the stock muffler to a B & B muffler but it is loud. I am turning a 18x10 prop 7250 rpm after changing muffler. Thanks Wayne M.

My G45 with CH ignition and a Bisson muffler modified with 1" exhaust pipes.
TNC tach and Amsoil Dominator mixed at 50-1 as per the instructions on the bottle.

Menz 22x10 ultra 6800 rpm
Bolly 22x10 carbon 7100 rpm

Great little engine!

Good Luck!
John

Thanks Johnny, That is great numbers on your G45, not far behind a G62. I tryed a 22x6 prop and could not turn it. That is way ahead of the US41. Thanks again Wayne M.

Those are G62 numbers, you have the best running G45 in existence..

Not quite. My G-45 does about the same - 6800 with a 22-10 Check carbon fiber( I cant spell the name). It has your Hall effect conversion and a C&H ignition + about 20 hours running time. (B&B muffler)