EZGO compression

berthasquare · 01-02-2011, 07:23 PM

What is the compression threshold for a 350 cc engine? Do ill-fitting valves have an effect on compression? In short, if I replace or at least do a valve honing (is that the proper term?) job, will my compression improve from its present 125?

Dave Box · 01-02-2011, 07:55 PM

The way to tell is to pour a little engine oil into the spark plug hole and retest your compression. The oil will temporarily seal your piston rings, so if the compression improves then the rings are worn. If the compression does not improve then it is being lost either through the head gasket or worn valves. In either case you are justified in removing the head and reseating the valves.
I hope that this answers your question
Dave.

scottyb · 01-02-2011, 08:12 PM

Compression under 145 is very suspect. Adjust the valves and see if it improves. They need to adjusted periodically for maintenance to keep the seats from burning up anyway ~ So just do it LOL

berthasquare · 01-02-2011, 09:23 PM

Thanks Dave and Scotty. Will do as recommended. Is it possible, at all, to do valve grinding without replacing the valve stem seal? Can valve seals be "saved" as it will take me some time to get replacement?

Dave Box · 01-03-2011, 08:58 AM

Sure you can reuse your stem seals but you will be heading down a path of tears. As I like to say it is your cart, your money and your call but if it were me I would hang fire and wait until I had new seals.
If you do regrind your valves a tip the old guys use is to reassemble the valves and springs, turn the head upside down and fill each chamber with kerosine. Leave over night and next morning look under the head. If there is any kerosine on the end of a valve stem you need to rework that seat.
Dave

mannyvillegas · 01-03-2011, 04:35 PM

Thanks! Good advice.

Dave Cicone · 04-03-2015, 09:36 AM

I have a 1987 ezgo 2 stroke i have installed a new carb drained old fuel put in new compresssion is about 90 psi i have installed new cables to attach the the governer
when i try to start it with starter fuild its hard to start when it does start it reeves up and i have to shut it down or it will keep going it has great spark.and has a electric fuel pump belts are new what the heck is wrong with it can any help please

thanks Dave

Rep · 04-03-2015, 10:28 AM

^^^^ Dave: See Scotty's post. ^^^^

Quote:

Originally Posted by scottyb

Compression under 145 is very suspect. Adjust the valves and see if it improves. They need to adjusted periodically for maintenance to keep the seats from burning up anyway ~ So just do it LOL

cart around · 04-03-2015, 12:09 PM

His is a 2 stroke, and has nothing to do with the rest of this thread. He should start his own to avoid the confusion.

Electric fuel pump is a mistake.

Hard to start could be worn crankseals, or gummed up carburetor.

Run away after start is carburetor being rigged wrong, and not closing all the way.

90 psi compression is bare bones minimum. 120 is more like it.

01-02-2011, 07:23 PM	#1
berthasquare Getting Wild Join Date: Apr 2010 Location: los angeles Posts: 126	EZGO compression What is the compression threshold for a 350 cc engine? Do ill-fitting valves have an effect on compression? In short, if I replace or at least do a valve honing (is that the proper term?) job, will my compression improve from its present 125?

01-02-2011, 07:55 PM	#2
Dave Box Respect the Cart Join Date: May 2010 Location: Rocky Mount, Virginia Posts: 2,190	Re: EZGO compression The way to tell is to pour a little engine oil into the spark plug hole and retest your compression. The oil will temporarily seal your piston rings, so if the compression improves then the rings are worn. If the compression does not improve then it is being lost either through the head gasket or worn valves. In either case you are justified in removing the head and reseating the valves. I hope that this answers your question Dave.

01-02-2011, 08:12 PM	#3
scottyb Happy Carting Join Date: Dec 2007 Location: Southern California Posts: 73,408	Re: EZGO compression Compression under 145 is very suspect. Adjust the valves and see if it improves. They need to adjusted periodically for maintenance to keep the seats from burning up anyway ~ So just do it LOL

01-02-2011, 09:23 PM	#4
berthasquare Getting Wild Join Date: Apr 2010 Location: los angeles Posts: 126	Re: EZGO compression Thanks Dave and Scotty. Will do as recommended. Is it possible, at all, to do valve grinding without replacing the valve stem seal? Can valve seals be "saved" as it will take me some time to get replacement?

01-03-2011, 08:58 AM	#5
Dave Box Respect the Cart Join Date: May 2010 Location: Rocky Mount, Virginia Posts: 2,190	Re: EZGO compression Sure you can reuse your stem seals but you will be heading down a path of tears. As I like to say it is your cart, your money and your call but if it were me I would hang fire and wait until I had new seals. If you do regrind your valves a tip the old guys use is to reassemble the valves and springs, turn the head upside down and fill each chamber with kerosine. Leave over night and next morning look under the head. If there is any kerosine on the end of a valve stem you need to rework that seat. Dave

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01-03-2011, 04:35 PM	#6
mannyvillegas Getting Wild Join Date: Nov 2010 Location: California Posts: 93	Re: EZGO compression Thanks! Good advice.

04-03-2015, 09:36 AM	#7
Dave Cicone Not Yet Wild Join Date: Mar 2015 Posts: 5	Re: EZGO compression I have a 1987 ezgo 2 stroke i have installed a new carb drained old fuel put in new compresssion is about 90 psi i have installed new cables to attach the the governer when i try to start it with starter fuild its hard to start when it does start it reeves up and i have to shut it down or it will keep going it has great spark.and has a electric fuel pump belts are new what the heck is wrong with it can any help please thanks Dave
Dave Cicone Not Yet Wild Join Date: Mar 2015 Posts: 5

04-03-2015, 12:09 PM	#9
cart around Test before replacing Join Date: Aug 2013 Location: Ohio side of the Pennsylvania border. Posts: 3,495	Re: EZGO compression His is a 2 stroke, and has nothing to do with the rest of this thread. He should start his own to avoid the confusion. Electric fuel pump is a mistake. Hard to start could be worn crankseals, or gummed up carburetor. Run away after start is carburetor being rigged wrong, and not closing all the way. 90 psi compression is bare bones minimum. 120 is more like it.

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