Hard Pull, too much compression !!

[touch107fm]

Hi Guys

I posted in the last post 'hard pull' that I am having the same issue.

I have contacted HE paramotors and they have been ace, replied to my email in great detail and have sent a free gasket to me here in OZ.

I am in need of your advice I have never taken apart a two stroke engine or any engine to be honest. I know my way around cars etc but have never gone this in deep with a engine.

So my story like the previous post is my engine is nearly impossible to start via pull start when you remove the spark plug it becomes manageable again. Too much compression.

Email from HE:

For the problem you are experiencing with your engine, there are 2 sources:

1. This procedure is correct if your engine was easier to start to begin with and is now harder to start.

The high compression can be due to the carbon residues accumulating on the cylinder top. These components are left over after each explosion. They accumulate and leave less room for the gases to expend (thus making the compression harder).

For this particular situation, the solution is easy. Put the cylinder head back together (you will certainly need a new O ring vitton gasket). The pressure on the cylinder head bolts is 1.8Kn.

Then make sure that the oil / fuel ratio is 2.5% (i.e. for 10L, you add 250ML of oil. You then have 10,25L of mixture). For the running in procedure this percentage is higher (3%). The running in procedure only lasts for 20L. After which you go down to 2.5%.

2. If your engine has always been hard to start (you haven’t noticed any change) then the factory compression settings are too high for you (some customers prefer their engines to hard to start because they want maximum power – competition pilots), then adding a base gasket between the crank casing and the cylinder is the solution.

So manufacture have sent me a new gasket, I have removed with great care the head and I have been instructed to clean the head and chamber.

Here is a few pics of the head removed:

Fingers crossed the gasket will fix the issue

Any tips or recommendations on the best way to go about cleaning the chamber and piston head.

Thanks in advance.

Darragh

[clivefreeman]

First thing which i did was to put some two stroke oil round the top of the piston to seal the piston. As to stop all the crap from going down the barrel, then when you are finished cleaning lower the piston and wipe the oil and crap away. As for cleaning i used a very fine grit wet and dry (600) A scouring pad and some petrol and two stroke oil Came up a treat. Have you tried a foot strap thats what helped me in the end for some reason it realy helps dont feel the compression or kick back, takes a bit of practice with balance though.

Good luck , hopefully see some flying videos of you soon.

Clive

[alan_k]

Darragh, this is the article to read:

http://www.aerocorsair.com/id107.htm

Cheers,

Alan