| Author |
Message |
    
Old Blue
Member
Username: oldblue
Post Number: 13
Registered: 07-2007
| | Posted on Tuesday, April 15, 2008 - 11:34 pm: | 
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#40973R (Evinrude 40hp, 1969)
I've got a basic auto compression tester and plan to check my two cylinders. Can someone spell out what I need to do. I think that the compression should be somewhere around 100+ lbs on both and readings should be close to each other. What throttle position do I need? Do I ground the indiv wires during each test? Do I crank ign 4-5 times and then record/reset? Is this right?
Also, what are the correct plugs I should use for this model?
Thanks for your help,
OB |
Joe Reeves
Senior Member
Username: joereeves
Post Number: 5886
Registered: 02-2001
| | Posted on Tuesday, April 15, 2008 - 11:41 pm: |
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No need to move the throttle off idle. Remove both spark plugs. Do something to keep the loose spaek plugs wires out of your way if you intend to crank the engine via the ignition key (spark).
With the compression tester inserted, four or five revolutions of the engine would be sufficent.
Use either Champion J4C or J6C spark plugs, gapped at .030. The J6C might give the engine a slight performance improvement. Try both. |
Andy Woodhouse
Member
Username: jafa39
Post Number: 26
Registered: 04-2008
| | Posted on Wednesday, April 16, 2008 - 05:24 am: |
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Compressions should be within 10% of each other.... |
Old Blue
Member
Username: oldblue
Post Number: 14
Registered: 07-2007
| | Posted on Wednesday, April 16, 2008 - 08:14 am: |
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It's a good day -
Upper 120 lbs, lower 124 lbs. I ran the tests on a cold motor - will this make any difference? How long should the reading stay? I waited a few minutes and saw no change so I was happy.
I found NGK B6S plugs gapped to .20 on my motor and will change them out and get proper gap of .30. They were not too fouled but I am going to switch to the champion options and see.
I am running 1:48 oil mix (I put a pint of oil in my 6 gal tank) is that going to be fine?
Thanks again |
Joe Reeves
Senior Member
Username: joereeves
Post Number: 5887
Registered: 02-2001
| | Posted on Wednesday, April 16, 2008 - 01:52 pm: |
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The correct mixture is 50/1. That is 1 pint of 50/1 TCW-III oil to 6 gallons of gasoline. Your 48/1 mix is close obviously. |
Old Blue
Member
Username: oldblue
Post Number: 15
Registered: 07-2007
| | Posted on Wednesday, April 16, 2008 - 11:41 pm: |
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Thank you Joe and Andy,
I'll let you know how it all goes- the lakes have finally thawed out so I'll get a test run done soon once I've finished some re-wiring and new gauges, impeller and so on. It's good to know my motor has good comp, next step is to ensure proper burn. I've been pretty lucky so far.
Thanks again for the help.
OB |
Terry G Stewart
New member
Username: 4uterry
Post Number: 1
Registered: 05-2008
| | Posted on Sunday, May 11, 2008 - 01:27 pm: |
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I need to know the head bolt torque for J15ECEC
15 hp Johnson. |
