72 'Rude choke on when key turned to run?

adamjr

Petty Officer 1st Class
Joined
Jul 23, 2009
Messages
272
I have a 1972 Evinrude 125283R 125 HP.

I'll start by saying that I got this boat in a cluster of a deal with the intention of repairing the hull it's on. I started the work on the motor first last year and with fresh gas in the tank and not very much work she ran after sitting for I have no idea how long before it sat untouched in my driveway for 3 years. Actually she ran really well.

First the question, then some background. When you put the key in and turn it to the run position the choke pulls down about half way. The choke has it's own separate toggle and hitting that causes the choke to pull the rest of the way. Is this normal?

Never one to leave a good thing alone and with a factory manual in hand I went over the wiring on the power head side of things. There were some wires hanging unattached in the control box and this being my first outboard I wanted to know why. From my recollection the things that were in the wrong places at the terminal block had to do with the thermoswitch. There was also a jumper wire (not the factory jumper of which there are 3) which I removed because it didn't belong there. The weather turned bad so I fogged it and that was it for the winter.

I sustained an injury which will prevent me from doing the major work the hull needs to be water worthy. It's a shame because I really like the boat but boats like it pop up on Craigslist for under $3000 so someday I'll just buy one that's water ready. But I digress.

I wanted to make sure the motor runs before trying to sell it and it's been another cluster. I put my battery on it and withoiut doing anything at the control side I had it almost started then nothing. It cranked over and fired but only as long as the key was in the start position. Then it wouldn't even crank. That turned out to be two simple things after a lot of troubleshooting. One was that the low throttle cut off was out of position so the throttle would have to be pulled all the way back. I adjusted that and I could hear the solenoid engage but no cranking. I noticed that the starter drive gear was under a tooth on the flywheel and jammed. A quick counter-clockwise turn with a 3/4 wrench resolved that and I got it to crank and fire but not run.

Prior to resolving the two simple issues I made sure the ignition switch (not OEM 3 terminal type) was wired correctly. All wires were in the correct place on the shift switch box and the ignition switch. I used a continuity tester and verified the ignition switch was operable. I also checked that the shift switch box was showing continuity in all of the correct places.

The thing that seems new is when you put the key in and turn it to the run position the choke pulls down about half way. The choke has it's own separate toggle and hitting that causes the choke to pull the rest of the way. I don't recall this happening before changing the wiring as stated.

Additional info: according to the manuals test procedures the blocking diode is shorted, the diode/lead assembly is good. The hot horn makes a clicking noise when the key is in the run position. The thermoswitch on the starboard top cylinder has continuity to ground which I believe means it is shorted and bad. It's current state is that I can crank it and it seems like it wants to run but I can't keep it running once the key is let go of.

Any ideas?
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
Re: 72 'Rude choke on when key turned to run?

Whew! Well the last paragraph says you have a lot of other issues, but the choke isn't one of them. It is working exactly like it is supposed to work. The half-way part is the warm-up function, keeps it from stalling before it gets warmed up. Once warm, it will no longer half-choke.

Having said that, there is a service bulliten telling how to defeat that function if it causes grief when starting a warm motor. I say, for now leave it alone and don't complicate things.
 

adamjr

Petty Officer 1st Class
Joined
Jul 23, 2009
Messages
272
Re: 72 'Rude choke on when key turned to run?

Thanks FR. What would be your suggestion for a next step?

If I am reading the manual correctly the thermoswitch should be OC when cold. It seems like quite an ordeal to change it. I want to get it running first and worry about the rest once I can get it started.
 
Top