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I have a Honda GX390 rope start pressure washer with several hundred hours. I used it a week ago and noticed it appeared to bog done slightly when I released the wand trigger (just for background). Now, when I try to pull the rope, the compression is so high it I can't pull the rope. I removed the pump and it is fine. I removed the spark plug and it is easy to pull. The valves seem to work properly, although I did not check the lash. I pulled the head and everything seems ok. Any Ideas?

From the description of the problem it sounds like an ACR failure of the camshaft.

First make the valves are adjust to spec. Then on one of the valve (I think Honda is exhaust) there should a slight bump of the rocker as you approach TDC compression stroke. IF not present then either the spring on the camshaft's ACR has broken or the complete ACR failed. But tearing into the engine please check for the ACR bump as it can be another problem.

Be careful as the last GX390 I had an ACR failure badly sprain my fingers from the compression kickback.

I’ve seen plenty of pressure washers where the pump under inlet hose pressure will make it extremely hard to pull over and start. The only solution I’ve found is to hold the wand in the open position, water coming out under only hose pressure, then try to start the engine. If it is now easier to start you will need to use this method in the future. The cheaper pumps do not have a bypass system to prevent a pressure buildup when the engine is not running. Warning, never try to start these cheaper units without the water turned on. You will burn the pump out very quickly, as the water acts as the cooling agaent for the pump.

StarTech said:

From the description of the problem it sounds like an ACR failure of the camshaft.

First make the valves are adjust to spec. Then on one of the valve (I think Honda is exhaust) there should a slight bump of the rocker as you approach TDC compression stroke. IF not present then either the spring on the camshaft's ACR has broken or the complete ACR failed. But tearing into the engine please check for the ACR bump as it can be another problem.

Be careful as the last GX390 I had an ACR failure badly sprain my fingers from the compression kickback.

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Thanks for the quick reply. That makes sense. I have notice that I am getting more more kickbacks lately.

One more question. I am re-installing the cam shaft in my Honda GX 390. I know the punch mark on the cam shaft needs to align with the punch mark on the crank shaft. Both gears have helical cut teeth. When I insert the cam shaft, it rotates slightly. Should the punch marks line up as the teeth engage or after the gear is fully seated. Once fully seated, it has rotated and the punch marks are now not aligned. Thanks in advance for the help.

If I remember correctly it they should after the gears are fully meshed. But one to double check is by looking at the counter balance shaft alignment which also has helical cut gear teeth. Hoefully it hasnt been removed.

My experience says fully seated.

A high-pressure washer will have a bad pressure if you pull the hoses and ropes it comes in contact with. Check if you have any accessories, try to use the tree pulling rope for the garden, washing items. Check the condition of the nipple and the connections, because the pressure that will interfere with the work depends on them. I took myself an adapter so that this oscillation of the waves is not so strongly felt when you turn it on and the pressure from the water starts abruptly. There are triple adapters that help distribute the pressure inside the system.