Tohatsu MFS 15B won't choke; won't crank

[End of the Road]

My first post so I'll improve with time (hopefully). I just bought a 2001 Tohatsu MFS 15B (Ser # 11095) and it is hard to crank (to say the least) the first time. After it is cranked the first time it cranks and runs fine for the rest of the fishing trip. I discovered that the two wires on the carb (auto-by-starter) were not connected. Connected them but no difference. Took carb off and cleaned (four different times) with no results. Reamed out all passage ways that I could find and cleaned with carb cleaner (did not soak) each time. Upon removing the auto-by-starter I discovered that the brass pin was detached from the plastic housing because one of the plastic prongs was broken and missing. Took the pin completely out to see if it had anything to do with the choke - no difference. Glued the pin back to the plastic housing and no difference. Did put 12 volts to the unit and verified that it moved outward when the element heated. I can cover the breather intake with my hand and have someone turn the key on the control box and it cranks right up (choked). Can someone explain to me how this carb is choked? The manual for this year model says nothing about choking the engine to crank it. Also, if I buy a new carb to fix the problem, can I buy a carb for a 20hp engine and will it bolt on without any modifications (remember, this is a MFS 15B)? A lot of rambling but would appreciate any advice.

 

[pvanv]

First off, apparently it does crank (turn over), but not start.
The ABS solenoid is supposed to allow the carb to be rich when cold, and then the pin extends out, leaning the mixture. The needle must fit into the port in the carb body, and the passageway across the carb bowl that feeds the accelerator pump/ABS must be immaculate. If the pin was broken off, it probably is shot, even though you glued it back together. This is a reasonable precision fit. You also need to verify that you have 12v going to the ABS when the motor is running.
In that vintage, there wasn't any 20 hp model. A carb for a 20C will not fit/work properly, and in any event is manual choke.

You may need a new ABS solenoid.

3R3034100M

AUTO-BY-STARTER ASSY

$165.78

Never ream any carb passage, as scratches can cause issues.

 

[End of the Road]

Paul
Sorry about the delay in answering back. You are obviously correct about the cranking/starting. I think that I have the pin back in the right position but could be wrong. I did hear that there is only a 3-5mm travel in the pin so I wouldn't have to be off much for it to ineffective.
I did discover that I could pump the throttle lever up and down about three times and leave it about 1/3 open and it will crank. Kind of like the 50-60's cars. They were temperamental and you had to learn their cranking procedure. I'll try this for a while and see if I can live with it. If not, I'll get a new carb and put it on. I think for the difference in price that I would go ahead and change the whole carb out and be through with it.
Thanks for the heads up on the 15hp to 20hp chnage-out. I see that mine is older and not a candidate. Would have been nice but I can certainly live with what I have.
Again, thanks for the help,
Fred