Home › Forum › Ask A Member › 1955 Evinrude 25hp Big Twin No Start
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gameroomfan.
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May 11, 2018 at 5:54 pm #9893
-Greetings Folks
My first post to this forum, albeit I have used it as a valuable resource frequently in the past. Quick background – I own 2 Gale Buccaneer 1957 25hp motors (one in process being refurbished, the other as a spare parts unit); and a 1955 Evinrude Big Twin. I have Gale/OMC service & part manuals which I am using exetnsively on the projects. Pictures are here (hopefully, they are accessible – if not please let me know):https://photos.google.com/photo/AF1QipN … 08cHKWsj8D
https://photos.google.com/photo/AF1QipM … h69JilgmOY
https://photos.google.com/photo/AF1QipM … _IfqOdE48N
https://photos.google.com/photo/AF1QipM … _IfqOdE48NThe subject of this post however, is the Evinrude. I picked this up last year through CL, and got the usual "I had it out last summer, and it ran great…" from the buyer. HA! Alas, I began to tinker with it a few weeks ago (plan to put in on a jon boat for still water flyfishing), and it will not start.
I have rebuilt the carb (which was originally quite clean) which included gaskets, new needle packing, adjusted the float, replaced float needle. Also, checked for spark using a China Freight spark tester, checked compression 65 – 70 which I considered acceptable (I am at 6200 ft, so Im guessing 10% better due to altitude), adjusted the throttle cam, etc etc.
Results are carb flooding, (some mild leakage from carb throat), and an occasional pop! backfire through the exhaust. Thats it. I have double checked various items originally done listed above, still no start.
Before I go further, like pulling the flywheel to get into the ignition & coils (I think a am getting some spark, judging from the spark tester and backfire), I was looking for some feedback & opinions from the group.
Sorry for the long post, but thought it helpful to provide enough info for remote diagnosis. 🙂
thanks in advance! alex
May 11, 2018 at 6:15 pm #75793It would definitely be worthwhile to pull the flywheel and inspect the coils. If they are originals they will be cracked and useless. The capacitors aka condensers also would be suspect and should be changed.
May 11, 2018 at 6:21 pm #75795To begin, I don’t have first-hand experience with this engine. And there are people on this board that have WAY more experience than I do. That said…..
I had *identical* issues with a 1954 15HP that I rebuilt. Like you, I had gas, good solid spark, air…but only got the occasional ‘burp’ out of the engine. Rebuilt the carb twice with the same results.
I’ll spare you my frustrations & cut to the chase: One day…and I don’t know what prompted me to do it….but that sintered metal gas filter that hangs under the carb? I put one end in my mouth, my thumb on the other end & blew. Nothing. Nada. Zip. Plugged solid! Took out the filter & put the bowl back on just to see what would happen: started on the very first pull of the rope.
Does your carb have a similar filter in a bowl under the carb? Might be the culprit….
And irrespective of whatever the problem turns out to be, I would add: even if you are getting spark, if the coils are original, change them anyway.
May 11, 2018 at 6:43 pm #75797Have had similar issues with 1950s big twins. Even though the carb was rebuilt and I had replaced the needle gaskets, added needle gaskets were required. Apparently the needles were not sealed. Believe the result was too lean a mix. Now anytime I notice poor starting or running is insensitive to needle settings I look to add needle gaskets.
On these running engines pre 1955 I saw compression in the 90s. Post 1955 saw compression in the 130s. I am near sea level so don’t know a correction.
May 11, 2018 at 7:12 pm #7579860-70 pounds is very low. Even at 6200 ft (i used to live at 9701 ft), your numbers should be higher than that. Even if you get it running, it won’t idle worth a crap. Look through the bypass covers and pull the cyl head. Look the thing over and see why you’re having such low numbers. I wouldn’t invest much into that one until you determine compression is no longer the issue.
May 11, 2018 at 7:51 pm #75799I have seen problems with weak magnets on the flywheel. If you have another flywheel close to same size, stick a screw driver to the magnet and then compare it to the magnet on your current flywheel. If it’s weak, replace.
May 11, 2018 at 8:16 pm #75800ALL, as in ALL 1955 Evinrudes have bad (cracked) coils unless they have already been replaced. But deal with that compression. And post the serial number. Some 1955’s had a serious problem.
May 11, 2018 at 8:49 pm #75805http://162.144.28.33/lib/johnson/manual … on.html#/0
bible if you do not have it
Joining AOMCI has priviledges 🙂
May 11, 2018 at 10:01 pm #75808Have you tested that meter on other motors? Perhaps it always reads low. If it is reading correctly, that is too low for a Big Twin. Might be stuck rings, might be worse. That would be my primary concern,
If all is well there, pop the flywheel. The flywheel key may be sheared, bare minimum you need to go through the ignition.
Keep us posted.
May 11, 2018 at 11:10 pm #75811Thanks so much for the quick and thoughtful responses & suggestions, gents!
Looks like I got some more ‘digging’ to do. I was hoping to avoid more disassembly, but I kinda figured I needed to take a look see at the coils anyway. Will follow up and investigate suggestions on compression, fuel filter, etc advice as well.
I will make a list and get back when I have completed the addtional diagnosis work. Might be a week or so.
Again, appreciate folks taking the time for input.
Alex
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