Compression Test Help Needed Please
Thread Starter
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New User
Joined: Apr 2019
Posts: 10
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Compression Test Help Needed Please
Hi Everyone, I'm back again.
First i want to thank everyone for all the help i have received. My new issue i am working on is severe oil burning. I have heard lots of things to do but wanted to get some opinions here before i do anything. The only thing i knew to do was perform a compression test. Here are the results:
1 - 85PSI
2 - 85PSI
3 - 85PSI
4 - 90
5 - 90
6 - 95
7 - 100
8 - 87
There is oil blowing out through the breather and into the air cleaner. The engine starts first try every time and actually runs rather smoothly. I am just not sure what to do next. Any recommendations? Thanks in advance!!!
First i want to thank everyone for all the help i have received. My new issue i am working on is severe oil burning. I have heard lots of things to do but wanted to get some opinions here before i do anything. The only thing i knew to do was perform a compression test. Here are the results:
1 - 85PSI
2 - 85PSI
3 - 85PSI
4 - 90
5 - 90
6 - 95
7 - 100
8 - 87
There is oil blowing out through the breather and into the air cleaner. The engine starts first try every time and actually runs rather smoothly. I am just not sure what to do next. Any recommendations? Thanks in advance!!!
Thread Starter
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New User
Joined: Apr 2019
Posts: 10
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I warmed the engine up for 15 minutes but the throttle plate was closed. This was the first time i did it and used a procedure i found which told me to warm for 15 minutes then remove one plug at a time and cold crank the engine. i did diable the coil and the fuel pump. Did i do this wrong and what it correct method? Thanks
Logistics Pro
Joined: Mar 2005
Posts: 4,698
Likes: 47
From: Mexico, Missouri
The throttle plates need to be in the wide open position. And the engine warm helps narrow down problems.
You can also add a little oil to each cylinder as you Do it to help with the results. Dry and with oil are 2 different results and pinpoint problems.
You can also add a little oil to each cylinder as you Do it to help with the results. Dry and with oil are 2 different results and pinpoint problems.
Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
Have to remove all the spark plugs first. Where did you get those compression test instructions??
Block open throttle all the way and open choke. Then perform the test. Engine should be fully warmed up, but this is widely ignored because removing plugs on a hot engine isn't fun. If good, consistent numbers across all cylinders are found with engine cold then it's probably more than a "good enough" test.
Battery must be fully charged and in good condition. I think you'll like the compression numbers a lot better after performing this operation correctly. A mechanic's vacuum gauge can really do quite a bit of engine health diagnosis too. It doesn't replace a compression test exactly, though it's close and a lot less hassle to setup.
Block open throttle all the way and open choke. Then perform the test. Engine should be fully warmed up, but this is widely ignored because removing plugs on a hot engine isn't fun. If good, consistent numbers across all cylinders are found with engine cold then it's probably more than a "good enough" test.
Battery must be fully charged and in good condition. I think you'll like the compression numbers a lot better after performing this operation correctly. A mechanic's vacuum gauge can really do quite a bit of engine health diagnosis too. It doesn't replace a compression test exactly, though it's close and a lot less hassle to setup.
Thread Starter
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New User
Joined: Apr 2019
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ok thank you for the insight. i am going to do this tomorrow. i will let you know how it goes. What kind of compression numbers should i be looking for?
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Laughing Gas
Joined: Oct 2014
Posts: 946
Likes: 186
From: Carnation, Wah
Even numbers! Gauges vary widely, so my 120 psi might be your 150.
I suspect you'll be ok- figuring that your crank speed was low with the plugs in,
you should see all of them go up 30- 40 psi. Which is fine.
hth
t
I suspect you'll be ok- figuring that your crank speed was low with the plugs in,
you should see all of them go up 30- 40 psi. Which is fine.
hth
t
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