darned thing wont spark...

[mikewhite]

Hi there i have a problem with an '85 merc 40HP that i have recently bought.
back in september i saw the engine running, started first time and pumped water fine, but was advised to get it serviced. I thought great, ?250 i'll buy it. the engine has sat since then in my garage... up untill now.

when i connected it up to my boat, i dutifully charged up my battery (and subsequently found that my charger was busted but that another story!), turned her over and she turned over fine but would not fire. After a new set of plugs I find that there is no spark.

I spent some time poking and prodding with a multi-meter and when i disconected the harness (it is connected with a 8 pin plug thingy - technical term that "thingy") i could find no continuity between pins 2 and 3 and the terminus of any of the wires on that side on the harness (wires to starter solinoid, wire to choke solinoid, earth(s), wire to unidentified 3 terminal back box, which in turn goes to switch box....) After some furious head scratching i noticed that that i could not feel the copper sleeve that the male end of the plug goes into.

Could this be the reason for the lack of a spark??
I am on kinda a zero budget!! is there a way of fixing the switch harness plug, or is it OK to carefully cut it off and reconnect with 8 bullet connectors??

Any advice would be great!!
(assume i know nothing - you wont be too far wrong!!)

 

[sschefer]

Re: darned thing wont spark...

Your trouble shooting efforts would be greatly enhanced if you spent just a little money on a good manual.

If it ran before and won't now, what did you do between then and now that might make a difference. Retrace your steps and you may find the problem.

A no spark condition can be caused by about a dozen different things so with the info you gave us it's hard to say yes or no.

I would not cut out the molded connector unless there was no other way. To answer your question though, yes you could replace it with water resistant bullet connectors. Use your multimeter to run simple continuity tests first.

 

[mikewhite]

Re: darned thing wont spark...

Sschefer, thanks for your reply:
RE: manual - i had thought to get a manual but for that i need a model and year. I have found out that it is a Mercury 40 blue band with a thunderbolt ignition but have no clue about the year. I researched the S/N (92990766) and found that it was amongst serials from Belgium during a period that mercury have no data for (some reason about paper recods going electronic??)!! Also the mechanic at the local boat yard has said that the engine has some parts which seem to be from a different merc. He has lent me a service workshop guide / manual for the Mercury 400 and i am doing my best to compare from this - but hey i'm happy to buy a manual if someone knows which one....

RE: retrace your steps - all i have done is disconnect the engine from the boat that it was on when i bought it, drove it home and stood it in the garage. I was kinda thinking it should start first time as it did before i bought it (10 months ago).

RE: continuity tests - i had the same thought!! first i thought i must have connected the key switch wrong, but all the wire colours matched OK. Afer that i figured that there must be a break in the cable that runs from the key switch to the engine, and hence disconnected the molded connector and continuity tested from key switch to the connector - all 8 lines where fine. It was only after this that i started attempting to compare wiring loom with that from the earlier merc 400, attempting to draw my own wiring schematic withcorrect colours (the merc 400 had differnt couours in the manual) this is when i found the dodgy connectors...