Polini Cylinder Head Screws/Bolts

One of the great things about ultralights is that they are even more flexible than experimental aircraft in what a pilot can and can't do with them (within the few FAA/FAR Part 103 regulations). Engines are a major part of any aircraft and many options are available for ultralights. This Forum is for that discussion.

Moderators: Badland-F5 Pilot, LA F2 Flyer

Post Reply
ksatter26
Posts: 426
Joined: Mon Feb 28, 2022 9:06 am
Location: Farmersville TX

Polini Cylinder Head Screws/Bolts

Post by ksatter26 »

I was having a lot of trouble getting my 303 to start. I replaced the factory battery with one with a higher Cold Cranking Amps ratiing and that helped some.

I did note that I had a small amount of oily grey/black material along the cylinder. I thought this to be some Evans Cooling Fluid overflow from possible overfill. When cleaning this up, I found that at least one of the cylinder head nuts was only finger tight.

I torqued the nuts (13.2 ft-lbs), the screws (8.8 ft-lbs), and the spark plug (14.2 ft-lbs). This seems to really help in starting the engine.

Since I previously only ran the 303 for less than an hour total during startup and test runs, I'm assuming the screws and nuts were untorqued from the factory.
Top
Post Reply

Return to “Ultralight Engine Talk”