Is there such a thing as too much compression?

Tarinazo

Seaman
Joined
Feb 18, 2019
Messages
55
I have a few threads here with a few issues I've come around while restoring my 1981 Bass Tracker III, lately my main focus has been on getting the 1981 Mercury 40hp (2 cyl) OB started... well today it did, barely.
With both sparks out, I can turn the flywheel with some resistance, putting my thumb over the spark hole produces a fair amount of compression, although I haven't done a proper compression test.
With both spark plugs on I can barely turn the flywhheel over using a rope and knot. Today, I tried to start the engine using jumper cables... the flywheel barely turns also, and because of this, the jumper cables started to smoke. So I tried to start the engine wrapping a rope around the flywheel... no luck.
I took the spark plugs out again and jump-started the flywheel again, it would spin freely, put the plugs back again and it's a no go.
Is this normal? is my wiring wrong? (still haven't found the correct wiring diagram, as stated in my other post), I have a big blue spark on both plugs.
Later today I got fed up and used a bit of starter fluid on the top cylinder, although I struggled again to turn the flywheel, the engine finally started up quite nice, it revved well, good stream of water out of the pee hole, it stayed on and warmed up good.
Once the engine ran for a while, I tried to turn it off but couldn't, as of now I have the BLK/YELL wire not connected anywhere, I touched it to the blue wire on the powerpack, nada, touched it to the wire from the tilt switch... nada, tuurned the key off at the remote, zero, puuled the lanyard and the engine kept running... I had to lower the carb setting to starve it.
Once it died, I thought maybe the engine loosened up a bit, it being still warm, so I tried to jump start it again only to come out with the same result: flywheel barely turning and the cable smoking after 3 seconds.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Depending on boaters age 30 and 40 HP motors are a nightmare to rope start, too much compression going on..

Happy Boating
 

Tarinazo

Seaman
Joined
Feb 18, 2019
Messages
55
Yep, found out the hard way. Upon doing lots more reading, seems to be a normal symptoms of an old starter or starter solenoid, I'll do a starter check and cleaning, also, I'll try to starte it from the key at the remote and not with jumper cables.
 

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
If you are smoking jumper cables, there is a good change of smoking the battery cables. Do short cranks with the key, don't grind away.
 

Tarinazo

Seaman
Joined
Feb 18, 2019
Messages
55
Cleaned the starter today, it had black gunky dust all over the insides. I took a light sandpaper to the contacts on the bottom part of the core, assembled everything back in the OB, connected my batteries and started it from the remote... the flywheel spun like it should. Sure enough it's going to start once I connect fuel into it.
Another thing is, I still don't know where to connect the BLK/YELL wire to... help!
 
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