Evinrude 4hp Light Twin 1973

dreamen

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I just bought a used 4hp that is in like new condition. Does not look like it has ever had a wrench on it. Was suppose to be in running condition. I am in process of getting it in top shape, cleaned carb, but it was clean, gas lines and plug wires are like new. Good impeller, just need to change the grease. I spirted a little gas oil mix in cyl's and tried to get it to fire. It did not?? I pulled plugs and checked to see if there was spark could not get any spark in either cyl?? I pulled flywheel and everything coild, points, condensors and wires look factory new. I would like to know if there is a way to test the coils, or if anyone has any suggestions. Points are set at .20 and are clean and shinney, coils are set like from what I have found on this site tight and flush with the mount. I just hate to change coils and find that they were not the problem. Appreciate the help
Thanks
 

hidef

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Re: Evinrude 4hp Light Twin 1973

Did you try cleaning the points? Just because they look shiny doesn't mean they aren't contaminated oil and grease can keep them from firing. The coils and condensers are independent of each other so I would start with the points. Use the attached link as a guide the 4 and 6 are close enough that it can help you.

http://www.sschapterpsa.com/ramblings/OMC_6hp.htm

I would change the fuel lines out the old lines are not ethanol resistant. Does it still have the cork float in the carb if it does you might want to change that out. I also wouldn't trust the impeller if the vanes are stiff and hard. You will want to run 25:1 premix in this engine too they still use bushings and wont last with 50:1.
 

dreamen

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Re: Evinrude 4hp Light Twin 1973

I found the video on how to test coil, will check that out and go from there. If coils are good I will replace the condensors. I did clean the points with 600 grit paper and cleaned with a clean towel. Its a start. Thanks
 

dreamen

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Re: Evinrude 4hp Light Twin 1973

I found a couple coils that came of a 3hp that seem to be the same. Will they work in the 4hp? I tested these coils and primary's are fine, secondary one is a 4.0 and the other 3.4 should they both be the same?
Thanks
 

hidef

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Re: Evinrude 4hp Light Twin 1973

The coils are interchangeable if they are from an older 3hp. You did degrease the points with lacquer thinner and some paper after you hit them with the emery cloth? Any particles in there can cause issues.
 

dreamen

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Re: Evinrude 4hp Light Twin 1973

Both of my coils on the 4hp register 4 on the plug wire side the other side was good. Not sure what is next unless I change the points.
???
 

SCG810

Cadet
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Oct 27, 2008
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Re: Evinrude 4hp Light Twin 1973

Hi, I had the same problem all was looked good but no spark.What I did is checked every thing same as you but I found out it was the leads to the coil, I just cut them about 3/8 off and push them into the coil. all good after that.

Steve
 

dreamen

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Re: Evinrude 4hp Light Twin 1973

I appreciate that info, but when I checked my coils I checked with the plug wire attached to make sure that they were connected to the coil and a good connection. Next?
Thanks
 

lindy46

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Re: Evinrude 4hp Light Twin 1973

If the coils, wires, condensers are good and points are clean and properly set, the only other thing is the plugs, which you didn't mention whether you checked. Did you check spark with a spark tester or just ground the plugs and look for spark?
 

dreamen

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Re: Evinrude 4hp Light Twin 1973

Just purchased a spark tester and will post the results. What do I torque the flywheel bolt too?? I never did post the model 4306C Serial E0005614
 

dreamen

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Re: Evinrude 4hp Light Twin 1973

This is a strange, deal. The spark tester show spark on top cylinder no spark on the bottom cycinder?? I tested the coil again and both tested fine. I reset the points on the coil that drives the lower cylinder and I got good spark. I put a little gas and oil in the cylinders and put in plugs and it fired. This was a first!! Yea!! Just need to hook up the tank and get this in some water and give it a try. Won't be till opening fishing. Will keep you posted. Just need to torque the flywheel bolt but need to know the torque pressure. Any ideas?
Thanks
 

dreamen

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Re: Evinrude 4hp Light Twin 1973

Is that foot lbs or inch lbs?
Thanks
 

tx1961whaler

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May 31, 2008
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Re: Evinrude 4hp Light Twin 1973

45 foot-lbs is correct . 45 inch-lbs is barely over finger tight
 
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