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Discussion Starter #1
I bought an older HS35 with the G150 engine. It takes 20 pulls to finally fire up.

I pulled the carb and gave it a good cleaning - removed the jets and cleaned them up. Put it back together and still VERY hard to start.

At what point do you fellas look at the valve timing and setting the lash gap? I am happy to try to clean the carb again and I want to pull the float drain to be sure it's getting a good flow of gas.

I also will do a compression check and see what that reads. I recall reviewing the G150 manual and it claimed the compression should be 85psi which seems really kind of low. Either way I will see what I am reading.

When do you investigate the vales in a hard to start 4-stroke?
 

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Check your valve clearance and if you take the head off, check your valve seats to make sure a seat didn't come loose in its base where it sets in the block because if it did, it will leak and cause hard starting, then you would have to 'peen' it back in place.
Then check your valve faces.
If the engine has an automatic decompression release, that will give lower compression numbers. On some GX engines it went bad and stuck in the open position, it is on the camshaft.
If you have tight valve clearance, the valve will not seal properly and cause loss of compression or if you do a 'leak-down' test, you will hear it leak out the intake or exhaust and then you know what one is causing the problem.
 

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We will assume you tried a new spark plug and guess at what else it could be. As ST1100 said, there is a compression release on the cam shaft of most engines to make starting easier.
If you engine lacks power, pops through the muffler or carb throat, the valves MIGHT need adjusting or lapping.
Also make sure the carb gasket is oriented correctly and the choke and primer bulb are working as they should.
 
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Discussion Starter #4
Thanks guys. I pulled the side cover off where I expected to see the valve rockers and only found access to the valve springs. It's an older G150 Honda engine. Are there some engines which don't offer the ability to adjust the valve lashing?

The Honda manual calls this engine a Slide valve system. Not sure what that is.

Thanks!
 

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I don't know about the Honda engine, but this video may help with diagnosing a valve clearance problem:
 

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I have a GC 190 engine that has been for the past 7 years, extremely difficult to start. A couple years ago I took off the air cleaner cover and filter and completely covered the choke hole. (stuffed a folded nitrile glove in there.) Starts in 1 or 2 pulls now and runs just fine. Stick the filter and cover back on. Done.
 

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To adjust the valves on the flat head engine you have to remove the valve and grind down the valve stems unless its a old Kohler K series. Some of those K series engines had adjustable lifters in them that you could adjust with a wrench, but you won't find too many of them on a snowblower, maybe on an old Walk-behind Gravely.
 

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Well, if it comes to the need to increase the valve clearance, you are going to need some guidance. First off you will need to remove the cylinder head and some equipment that will be in your way. Remove the exhaust also and the carb. So you will need gaskets for all those parts to replace reliably. You can use the engine clutches to move the engine which generally are counterclockwise. Note that valve positions in the block are not necessarily the same, intake may be right or left of the exhaust.

Here are 3 videos that will help you with the valve clearance. It is easiest with the springs removed so each video approaches that differently and adds touches that will help a first timer:




Note that the 3rd video has 2 mins or so of rubbish, but he knows what he is talking about and is an excellent communicator. I like seeing the valve stem end that is ground because he is an expert and I could never achieve that with a grinder.

Good luck.
 

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