E-start blew a fuse

Oildrip · Jul 7, 2020

Hi,

Finished up install of a new 3-phase stator, Pazon Surefire, Podtronics, DynoDave starter, new solenoid and some other work (carbs, layshaft bearing, clutch stack height, etc) to my 1975 MK3. Kickstarted the bike (2nd kick) and it runs great...very happy! Need to check timing, fiddle with carbs a bit but overall runs great...was able to take for a spin around the block. Then I decided to try the e-start button but nothing happened. Checked under the seat and found I had blown the fuse. So I pulled off the solenoid and hooked up 12v to the “s” terminal and the metal bracket plate of the body and nothing happened except for a spark. I took my old solenoid and did the same and it clicked/clacked. So I was just wondering if the new solenoid is my problem...first solenoid I ever bought and it’s a dud? I think I got the solenoid wiring right:

Thanks again for any help/advice!

L.A.B. · Jul 7, 2020

Oildrip said:
So I pulled off the solenoid and hooked up 12v to the “s” terminal and the metal bracket plate of the body and nothing happened except for a spark. I took my old solenoid and did the same and it clicked/clacked. So I was just wondering if the new solenoid is my problem...first solenoid I ever bought and it’s a dud?

From the description, it does sound like the new solenoid could be a dud.

Torontonian · Jul 7, 2020

Battery to which polarity ?
Something is shorting .
Reverse connections and stock up on fuses ? What's the problem using the original solenoid ? Mine's good after thousands of starts.

marshg246 · Jul 7, 2020

Oildrip said:
Hi,

Finished up install of a new 3-phase stator, Pazon Surefire, Podtronics, DynoDave starter, new solenoid and some other work (carbs, layshaft bearing, clutch stack height, etc) to my 1975 MK3. Kickstarted the bike (2nd kick) and it runs great...very happy! Need to check timing, fiddle with carbs a bit but overall runs great...was able to take for a spin around the block. Then I decided to try the e-start button but nothing happened. Checked under the seat and found I had blown the fuse. So I pulled off the solenoid and hooked up 12v to the “s” terminal and the metal bracket plate of the body and nothing happened except for a spark. I took my old solenoid and did the same and it clicked/clacked. So I was just wondering if the new solenoid is my problem...first solenoid I ever bought and it’s a dud? I think I got the solenoid wiring right:View attachment 17496
Thanks again for any help/advice!

Not an expert on MKIII. The two small terminals get White/Purple (not used with EI) and White/Red. Are you sure the White/Red is on the correct small terminal? Are you sure the wires to the two large terminals are not reversed? BTW, it's battery connection to check against, not the mounting plate.

EstuaryBoy · Jul 7, 2020

Didn't use my OE solenoid for a few years as I ditched the starter when I fitted a belt. Few years on bought an all singing, all dancing uprated starter, reinstalled the triplex chain et al.. About three push button starts later the solenoid stuck closed at the MOT station.... That was fun!!!

L.A.B. · Jul 7, 2020

marshg246 said:
The two small terminals get White/Purple (not used with EI) and White/Red. Are you sure the White/Red is on the correct small terminal?

White/red connected to the 'S' (switch) terminal is correct.

As everything else appeared to be working normally then the battery must have been correctly connected in the beginning.

For the separate solenoid test, it wouldn't matter as that type of solenoid shouldn't be polarity sensitive.
The original Prestolite solenoid operates regardless of the polarity.

marshg246 said:
Are you sure the wires to the two large terminals are not reversed?

They appear to be correct and as they are not part of the fused system they shouldn't be responsible for the fuse-blowing.

Oildrip · Jul 7, 2020

So apparently new isn’t better...I put the old solenoid back in and it fired right up. In hindsight I shouldn’t have bothered with a new one but I got the bike in the fall and thought replacing it as I did all the other work mentioned above was a good idea. I still can’t believe the one and only solenoid I’ve ever bought was a dud. Also, I don’t understand why it blew a fuse (but I am one of the electrically challenged members)?
At any rate...very happy to have my bike running...thank you again for everyone's response

concours · Jul 7, 2020

Where did you get it?

Oildrip · Jul 7, 2020

I found it at NAPA locally:

Torontonian · Jul 7, 2020

Made in Mexico, Not U.S.A.

concours · Jul 10, 2020

Bench Test it using negative ground/earth, see if it clunks as expected. Be sure & ground the mounting flange.

ebyker · Jul 10, 2020

looks like it needs ground on the other small terminal probably not internally grounded

L.A.B. · Jul 10, 2020

ebyker said:
looks like it needs ground on the other small terminal probably not internally grounded

The solenoid should be 'case earth/ground'.
Assuming the apparently faulty solenoid could be made to work then connecting the 'I' terminal to earth/ground(+) would be a dead short (also unfused) as the 'I' terminal is negative(-).

EstuaryBoy · Jul 10, 2020

Isn't that terminal for sending a full 12v to the ignition system whilst the starter is activated?? I seem to remember it becoming redundant when EI fitted (Or did I dream it?)

maylar · Jul 10, 2020

EstuaryBoy said:
Isn't that terminal for sending a full 12v to the ignition system whilst the starter is activated?? I seem to remember it becoming redundant when EI fitted (Or did I dream it?)

Yup. Connected via the white/purple wire.

The Buckeye Rider · Jul 10, 2020

It was hammered into us in trade school "a new part is not necessarily a good part". On a lighter side the teacher use to also tell us repeatedly "if it doesn't fit, force it".

E-start blew a fuse

Oildrip

L.A.B.

Moderator

Torontonian

marshg246

EstuaryBoy

L.A.B.

Moderator

Oildrip

concours

Oildrip

Torontonian

concours

ebyker

L.A.B.

Moderator

EstuaryBoy

maylar

The Buckeye Rider

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