93 sp electrical

[L.R.TNT]

Ok guys, I bought a 93 sp cheap. It runs great but starting it is kind of a pain when its warm. The way I start this thing is push the kill switch push start button(when its cold obviously pull the choke) then release the start button and it pops right off. When its warmed up its a bit of a pain because it requires 1/4-1/2 throttle to start like all the old rotary valve engines. It will start with out pushing the kill switch but it cranks with intermittent spark for a long time before it pops off.....

Any ideas?

Thanks in advance.

 

[Dr Honda]

What???


First... if the carbs are clean, and working... you shouldn't have to give it half throttle to start it. Basically... you have a flooded engine. It has nothing to do with "Old rotary valve engines."


The kill switch thing is confusing me. If the switch is bad... replace it. (unless I'm miss understanding)

 

[L.R.TNT]

All of my old rotary valve sleds were the same, if you lean it out to the point where it starts without throttle the plugs start turning white when cruising low speed... Is the kill switch an open or closed loop on this? And is there an OHM reading I can test for?

 

[Dr Honda]

You shouldn't have to "Lean out" anything. The needle and seat or the high speed check valve is leaking. So... when you shut down... the carbs leak the fuel into the engine. I restored at 90 Si, and it started, and ran like a champ. (it was the original +20 year old engine)

OR... if it's smoking a lot on start up... the center seals are leaking.


As far as the "Open, or Closed loop" on the kill wire... I'm not understanding that either. On this engine... you have a first gen MPEM. The switch tells the MPEM you would like to shut down the engine. I would start with removing the wires at the MPEM, and check to see if the switch is working. Also... check to see if it works when you move the steering around. I know it's in the "Dash" area, but the wires may be moving around with the steering neck.

 

[L.R.TNT]

You shouldn't have to "Lean out" anything. The needle and seat or the high speed check valve is leaking. So... when you shut down... the carbs leak the fuel into the engine. I restored at 90 Si, and it started, and ran like a champ. (it was the original +20 year old engine)

OR... if it's smoking a lot on start up... the center seals are leaking.


As far as the "Open, or Closed loop" on the kill wire... I'm not understanding that either. On this engine... you have a first gen MPEM. The switch tells the MPEM you would like to shut down the engine. I would start with removing the wires at the MPEM, and check to see if the switch is working. Also... check to see if it works when you move the steering around. I know it's in the "Dash" area, but the wires may be moving around with the steering neck.

Moving the steering doesn't change the condition. When I lean the low speed adjustment to get it to start without throttle it runs too lean under 1/3 throttle and my plugs turn white IE too lean. Crank them back out now there a nice golden brown but needs a little throttle to start it, after startup it idles fine.
By open or closed loop for the kill switch I meant does it ground out cutting power to the MPEM(open loop) or is it wired in line so when its pressed it disconnects voltage to the MPEM(closed loop) generally they are open loop type but when I disconnected the kill switch I had no power anywhere much like pushing it.

 

[RodInEscondido]

The wiring diagram is rather straightforward. In essence a ground via a lug inside the mag housing goes to the stop switch (nc) then to the tether switch (closed with the tether connected), then to the electronics AND the start switch (open until start is depressed then supplies ground to the solenoid to activate). Pressing the stop switch or removing the tether removes the ground from the electronics. I had a situation where the ground lug inside the mag housing was bad, but in that case the starter would not activate.

 

[L.R.TNT]

Awesome, thanks for the info. Sounds like a cheap easy fix for me!