ETLB Squawk Forums — Archive

The brand new Rotax 277 on newly registered minimax started today for the first time!
At 2,350 rpm vibration was severe and heard few missed fire. At 3500 rpm ran seem smooth.
Though I run it in short period of time about a minute or two since I'll be preparing for a break-in.
My question is , does spark plug electrode gap on CDI the same as contact breaker type?

Then I presume 0.4 to 0.5mm spark plug electrode gap still good regardless of ignition type. Thanks.

Phil,
I have no experience with a Rotax but had an issue with a Kawasaki 440 that my be of interest to you. I bought this engine used and was told that it had the CDI ignition so I set my plug gap to .025 or whatever it supposed to be for the CDI. Within the first few hours I had a cylinder go dead on takeoff because of no spark on one cylinder. After I pulled the flywheel I found a magneto ignition and not the CDI I was told it had when I bought. It turned out that the condenser had burnt out. I called a snowmobile dealer and gave hime the engine serial number so he could get the correct condenser and he told that my engine had a CDI ignition. He then ask me if this engine was used on an ultralight and I told him yes. He told me that many of the early ultralight pilots didn't trust the new CDI ignition that Kawasaki started using and switch back to the magneto's they were familiar with. The plug gap for the magneto was .015 to .018 and not the wide gap that I had set thinking I had a CDI ignition. It turns out the extra wide gap was causing the condenser to work harder had was over heating. No more ignition problems after that.
Dick

Dick,
I talked to a friend this morning, an experienced motorcycle mechanic who converted my old outboard motor with magneto ignition into cdi. That gap with cdi should be at 0.06 - 0.07mm. He advised setting should be at 0.07mm to insure good proportion of combustion that helped cyclinder head temp at lower reading.
Phil

Quoted from Phil Dick,
I talked to a friend this morning, an experienced motorcycle mechanic who converted my old outboard motor with magneto ignition into cdi. That gap with cdi should be at 0.06 - 0.07mm. He advised setting should be at 0.07mm to insure good proportion of combustion that helped cyclinder head temp at lower reading.
Phil

He must have meant 0.6 to 0.7 mm, I guess.

Quoted from Keith103

He must have meant 0.6 to 0.7 mm, I guess.

Oh yes, you are correct!
I'm sorry.