Murray WideBody Blown Head Gasket?

Hawk_91119

Hawk_91119

Member
I have an old Murray mower that I am repairing. It has the 14.5 hp single cylinder over head valve engine. It is very hard for the starter to turn the motor over unless the battery is fully charged. It blows a little bit of oil up the dipstick. It has a lot of compression, but it does not smoke. Do you guys think this is a head gasket failure?
 
I also forgot that it leaks a lot of oil, I had to clean a ton of it off the engine. But that could just be a valve cover gasket, which I am going to replace.
 
It runs fantastically. I do not know if the valves have been adjusted ever. It was my relative’s mower who passed away.
 
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if the head gasket failed in a serious way, compression would be way down rather than "It is very hard for the starter to turn the motor over unless the battery is fully charged." That implies the opposite of a blown head gasket - high compression. But why would anyone trouble shoot a starter problem using an under-charged or worn out battery? The first step would be to test the battery before and after charging, clean the terminals and ground etc..

The head gasket could be a little leaky in the scenario above where it might cause high breather pressure if the engine head has an oil supply or return passage. But say it is an L head engine like an old push behind Murray might be, then there is no place the combustion gasses can escape to except out.

Of course since you haven't listed engine model information it leaves everyone trying to read someone else's mind. My skills in doing that are a bit off lately. How are yours?
 
Engine Model Number: 287707
Type: 1272-E1
( A Murray WideBody is a ride on mower )
The battery was brand new, and still hasn’t cranked well. I have already cleaned the body ground. I have replaced the solenoid because it would not crank at all. It cranks and starts, but it can barely get past the compression stroke and it does things that are questionable, as I do not want to sell a mower with a blown head gasket.
 
You may have a collection of multiple problems.

The starting issue is more likely the compression release has failed. You can watch the valves or run a compression test.

The reason for excess blowby can be a head gasket but it can also be worn rings.

Valves can be out of adjustment too on top of these issues.

I might run a compression test, adjust the valves checking to see if the compression release bumps properly, and retorque the head(s) to make sure they are properly torqued and see what happens. It gets more complex if that doesn't solve it. Also check the exhaust screen if it has one (Spark Arrestor) to be sure it is not plugged. Look over the spark plugs while they are out to how new they are and the brand.
 
A little oil out of the dipstick is normal for any 1-2 cycle engine while they are running. It just the pistons moving up and down. Its the breather starts to have a lot of oil in its tube when there is a possible head gasket problem. This particular gasket is known to blow between the cylinder and the push rod galley. It mostly happens on the 31 and 33 series and not so common on the 21 and 28 series.

The only to be sure is to do a leak down test with the rocker cover off. That way you hear where the air is escaping the loudest at. If it is louder at the push rod galley then the head gasket blown. otherwise if it is at the dipstick then it comes down to if the leakage is under 20% or not. If over 20% then the cylinder/rings are worn.

But high compression is usually always a decompression problem which the first thing to do is to adjust the valves to spec and look for the ACR bump on the intake valve as you approach TDC compression stroke. If the bump is not there then it is a bad ACR on the camshaft.
 
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