1973/4 Evinrude 85hp

Mr. Algee

Recruit
Joined
Aug 17, 2005
Messages
2
Okay so heres the fun stuff. I spent 2 years completely rebuilding my boat and doing some general maintenance to the engine. Now comes along trouble. Last year when I would run the engine it was a hard start-cranking 10-12 times before it would run, and then it would stall out after about 5 min at idle/or if I put any load on the engine: ie put it in gear. About 10 days ago I brought the boat out of storage to prep it for the cooler fall weather and florida's 2nd boating season. I noticed now that instead of 10-12 times to turn her over it was considerably more. Finally when she was running if I throttled the engine down any lower then half throttle, she would stall. No matter how long I would play with throttle controls it would stall. Furthermore I noticed that when running at full throttle (not in gear) the engine pitch would flux. My buddy and I began troubleshooting. <br />We have pretty much ruled out a few things...although maybe further testing would prove us wrong. <br /><br />We replaced the spark plugs. With new plugs in we noticed no change. Upon some examinations we noticed the solinoids for 2 of the cylinders were pretty badly cracked so we replaced those. When we did that...it got worse. Now the engine will crank maybe sputter for a second then quit. For some reason now for the first time also, she has been backfiring every once in a while, mainly if I crank her for more than 5-7 seconds or so. We then took off the carbs and they were both looking pretty much brand new. No build up or gunk. Floats were nice, seals looked good, all parts moved nicely. We reassembled them and thats where we're at now. Looising patience as seems to be the trend at every stage of the rebuild so far. Unfortunately I'm not a trained mechanic so everything we have done has been a "learn as you go, hope you dont break it" experience. Hopefully we haven't broken it and someone out there can give me some suggestions as to what it could possibly be. I had a few ideas maybe Im way off, please let me know what you think.<br /><br />1. Bad gas tank/line- goo in the tank/line causing poor fuel flow. The reason that any fuel issues has been brought up--> right after I installed the new solinoid I had her run at full throttle once. Every time I heard the engine struggle I pushed in my electric choke for a second or so, she would die down just a bit more and then when I released the choke she would come back to life.<br /><br />2. Timing is off. Only began to think this after hearing her backfire <br /><br />3. Bad compression in at least 1 of the cylinders...but cant check for compression if I cant get her to run... or am I wrong about that?<br /><br />4. Pack went bad- so even with good coils-still no spark?<br /><br />Thats as much as I could think of without knowing more about anything. This engine is a hybrid of a few different 'rudes and may just be beat to hell and beyond all hopes. I have so far invested over 4grand into this boat and I really dont want to hear that...so any help at all would be so incredibly greatly appreciated :) . <br /><br />Thanks in advance <br /><br />Jay
 

Goodoleboy

Chief Petty Officer
Joined
Nov 20, 2003
Messages
555
Re: 1973/4 Evinrude 85hp

Welcome to forum!<br /><br />Did I read what I thought I read. You ran engine at full throttle while in neutral.<br /><br />Never...never...never...run an engine above mabey 1000 to 1500 at most with no prop load on engine. <br /><br />It will destroy its self. And quite possible you at the same time.<br /><br />At this point you have to run a compression test. Its dosent need to run first.<br /><br />Post back you numbers. Hopefuly you still have better than 100 on all four.<br /><br />Remove all plugs and spray good with wd40 in all cylinders and spin starter for a few seconds 5 or so and clear cylinders of oil.<br /><br />Test cylinders with all plugs removed. You can buy compression tester at any auto parts store.<br /><br />If it passes the compression test, then we will go from their, On getting your carbs clean and so on and so forth.<br /><br />You need an OEM service manual ASAP!<br /><br />Good luck!
 

bubbakat

Captain
Joined
Oct 29, 2002
Messages
3,110
Re: 1973/4 Evinrude 85hp

First thing is get you a manuel. This is a must.<br />You need to do a compression test.<br />Do a spark test. These selnoids you are speaking of , I am assuming is coils. Have it idleing on muffs and pull each wire and see if the sound of the engine changes. and by all means get fresh gas mix. From the backfire ing I would pull the flywheel and ck the key and see if it is sheared.<br />I have at times taken a rubber hammer and tapped the pack and see if it changed the running any.<br />But a spark test will determine this also.
 

Goodoleboy

Chief Petty Officer
Joined
Nov 20, 2003
Messages
555
Re: 1973/4 Evinrude 85hp

And please dont start another thread about this engine.<br /><br />Keep posting back on this same one as long as we are working on this engine, No matter what the problem is.<br /><br />It makes it very difficult to keep a train of thought going on engine if you dont. And alot of people wont even bother to try and help.<br /><br />Thanks!
 

Mr. Algee

Recruit
Joined
Aug 17, 2005
Messages
2
Re: 1973/4 Evinrude 85hp

Hey thanks for the tips off the top. First thing... about the "full throttle" thing. Its not really "full" so to speak...but as high as the start lever requires to start the engine. I never even put the boat in gear out of the water. Also... Im gonna be running numbers on the compression tonight. They should all be within 5-10 of each other right? One more thing... I pulled out the plugs on cyl. 2 and 4 (the ones we replaced the coils on) and still noticed no spark. I dont know if its something I'm doing wrong or something thats gone horribly wrong with the motor? Thanks for bearing with me.. I can glass like a mofo but when it comes to gears and stuff...Im a newbie :) .
 
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