Hey,

I thought I'd show my first conversion
I have no idea what brand this engine is, I'm assuming it's a Chinese 'no name' brand. I also do not know its displacement,
It was brand new when I found it and was missing the pull starter. The prop adapter was just made up from some hexagonal aluminium with the edges rounded off. I havn't weighed the engine but if anyones interested in knowing I'l do it. The flywheel has also been lightened.

I've run about 2 tanks through it and according to the tachometer I've got shows 13,100 Rpm at full thottle with the 18x8 APC prop.
I've been reading up about Rpms on converted engines and this seems fairly high, would running at this speed kill the engine? Although I found the engine so I'm not too fussed if it blows

The muffler gives me the creeps with its sad face, I didn't notice it until a friend pointed it out haha

The proper rpm should be 6800 - 7500 rom to utilize the torque of the engine

Is that as in much further than 7500rpm you are loosing torque?

I may have found a reason for the high rpms, the engine looks to be the same as a lot of the engines used to power motorised skateboards, which are advertised as 33 to 49cc, they all look the same, one day I'll open it up and measure it.... The engine the same size as some 25cc engines I have, but runs a smaller spark plug. a bit wierd

One possible explanation for a seemingly high RPM reading is the RF noise from the ignition, causing a false tach reading.

I know my Poulan 32 turns 7200 but at times I get tach reading of 14,000.

13K on an 18*8 is massively under propped if the reading is right. No way is it that the correct reading for 33cc and it's a big stretch for 49cc. 62 could spin at that revs (maybe).

If you are using a GloBee tachometer, they are well known for giving false high readings sometimes. You have to move them around until you get a "believeable" reading....

AV8TOR

You guys were right! the Tachometer was getting a alse reading from the ignition.

I was reading a lot about rpm's on these size engines and I was thinking how could some no name brand unmodified engine that I found be getting several thousand rpm more than what I'm reading about lol
It's definitly the same engine as what is on a lot of things like chinese motor scooters and motorised skateboards, and they are advertised as 33 to 49cc's, so I think they are false advertising there engines...
after reading of the 'standard' rpm range I knew something was up, after measureing it again today I get about 7300 at wot