GX270 Kickback

[Hammermechanicman]

Grasping at straws here. Make sure whatever is attached to the end if the crankshaft is tight. I have seen mowers with a loose blade kick back.

 

[HurstGN]

I wondered that myself but if I disconnect the spark plug, I can pull it over all day without any kickback. As soon as I reconnect the plug, it kicks back when I try to start it. That points me back to a timing issue.

When the plug is removed, there is 0 compression. To truly test without the plug, use a compression tester in place of the plug. That way you get compression and a reading of how much.

 

[jshep1102]

SUCCESS!!! Bertsmobile1 win the prize (if I had a prize to give away). I had the original magneto gap set at 0.010". I set the gap to 0.020" and it jerked out of my hand at 1/2 of a pull. I set the gap at 0.030 and it starts every time and runs great. I wouldn't have ever figured that out on my own. This forum comes through again!!

I'll put a label on the engine cover to remind me (or anyone else that may work in this pressure washer in the future) to set the gap at 0.030 to prevent this kickback issue.

Thanks again to all those who offered advice. Thanks most to Bertsmobile1 for figuring it out for me. WooHoo!!

 

[bertsmobile1]

With a gap of 0.030" there is something that is wrong.
Illingine is probably right & the timing chip in the coil is bad
But the old saying "If it is working don't try to fix it " comes into play

Have a close look at the exhaust for black smoke and check the plug for soot.
If the spark is too late then you get a build up of soot on the plug & exhaust valve .
You can fix the plug by going one or two grades hotter ( with NGK's ) but you can not fix the valve build up other than by turning the fuel off & starving the engine rather than using the ignition switch .
OTOH mower engines are very low tech lazy engines and will usually run quite happily over a massive range of mal adjustments
Also be watchful for signs of overheating but if it works then go mow .

For those who are unaware , the spark timing vs air gap is an inverse square relationship so 3 times the air gap is around 1.2 deg of crank rotation.
Those of you who play with Runtronics ignitions in your model aircraft will be familiar with this method of timing .
Yamaha also used it on some of their flywheel magneto motorcycle engines till they developed a much better ( thus expensive ) control module

 

[jshep1102]

Have a close look at the exhaust for black smoke and check the plug for soot.
If the spark is too late then you get a build up of soot on the plug & exhaust valve .

My buddy picked up the pressure washer today and will keep an eye out for these issues. If they appear, we'll order a new magneto and go back to 0.010 gap. Thanks again for all the help!!

 

[jshep1102]

Update - the pressure washer started fine for a while but recently started kicking back again while trying to start it. My buddy ordered a new ignition coil and set the gap back to 0.010". No change with the new coil. Still kicking back. I think I need to order a book of matches and some gasoline.

 

[bertsmobile1]

move the coil back another 0.005"
This will retard the ignition a poofteenth .

 

[Wolfepack88]

If its like the GCV200 mower the cam timing is off and there is a video on youtube showing how to adjust this. I had two brand new Honda HRX217HZA's both fail within 4 days of the first mow. Cam not working with automatic compression release so its firing too early. I also talked a honda mechanic that has 35 years and he said even though the service manual says adjust valves at TDC, he said go a hair past that because at TDC sometimes the automatic compression release still won't function. He's repaired dozens and dozens and that is the adjustment he makes. There is also a couple of videos on honda pressure washer valve adjustments.

 

[Metallitubby]

All, the GX270 and corresponding GX390 et al have a compression release issue. There is a new camshaft available to remedy this concern. If under warranty, any capable Honda dealer can replace the camshaft. I monitor these issues daily, so this is a fairly common occurrence.