1984 or 1985 mercury 25hp..need help please!!!! no spark now

[kennyboater]

i just purchased on old arrow glass boat with a 84 or 85 25hp merc.

the guy i purchased it from got it from a friend and had never started it or really tried.

before i pulled the boat home, i took out a spark plug and checked to make sure the motor had spark; to see if i just needed to give it a good carb cleaning.

so i took a plug out, put it on the block and had the guy pull the rope, no spark at first...made sure the handle was in neutral moved the motor around a little and tried the other spark plug...There was spark!

so i towed the boat home...now no spark... confused and frustrated...

so i started inspecting to see if any wire or anything fell of while towing home. upon inspection, and taking carb and engine cover off, found two wires coming from tiller handle to engine completely sheered off...

from handle, there are two throttle cables, and now these two wires that seem sheered off (cant tell when they sheered). i dont see where these two wires are supposed to go... HELP!

if this is the problem, how did i get spark before i towed it home? did they sheer off by moving engine around when towing home? (they are dirty without clean ends, so dont really look like they just sheered off on the tow home)

also, looks like someone wired a kill button into the engine...dont know is this could be the problem...

sorry this is so long, but i dont want to take it to a shop and have them charge me hundreds of dollars when im reasonably handy. any help you can give i will really appreciate.

are there any wiring diagrams out there?

btw, sorry this is so long, just confused how i could get it to spark before towing it home. now none... and how i cant find where these two wires are supposed to go and how they do not really look like they just sheered recently...

help please

 

[Laddies]

Re: 1984 or 1985 mercury 25hp..need help please!!!! no spark now

Start by removing the black/yellow wire from the switch box, that comes from the kill switches there should be 2 switchs. If you still don't have spark get back with the part number off the switch box and we can give you test info

 

[kennyboater]

Re: 1984 or 1985 mercury 25hp..need help please!!!! no spark now

thanks.

removed that black/yellow wire, still no spark...

also, think i figured something else out. i did not realize that on the end of my tiller handle there is a kill button. so the 2 sheered wires coming from the tiller handle and going to nothing look like they were for the kill switch. one is black/yellow. looks like maybe the swith went bad, so someone manually installed another kill button. this new kill button is connected to the black/yellow wire you told me to remove. so i removed, but still no spark. also, there is 2 wires on that one connection...are there supposed to be 2?

i will go get the part number off of the switch box...

thanks so much!

 

[kennyboater]

Re: 1984 or 1985 mercury 25hp..need help please!!!! no spark now

ok, so a prayed a got some good news. i was looking for the part number on the switch box. when i noticed a loose screw on the switch box. i put the black/yellow wire back on the switch box, tighteded the loose screw...and presto, got spark out of the top cylinder!!!!

none out the the bottom one...switched spark plugs to make sure that it was not the plug and still no spark out of the bottom cylinder...

where do i find the part number on the switch box?

now what? so i got spark out of the top one, none out of the bottom... should i switch plug wires to make sure that its not the plug wires?

thanks so much

 

[Laddies]

Re: 1984 or 1985 mercury 25hp..need help please!!!! no spark now

Your engine should fall in to a 339-7452A3 so here the test info from Rapair

 

[kennyboater]

Re: 1984 or 1985 mercury 25hp..need help please!!!! no spark now

finally got both cylinders to spark...put to carb back on and cranked it up. i really excited, the guy it got the boat from said the boat has not run for years!

2 more questions,

1. what is a good site to buy parts for my 25 hp merc?

2. where should i go to on this forum to talk about ripping up the fiberglass deck and rotten wood, and putting a new deck in?

thanks for helping

 

[15yroldmechanic]

Re: 1984 or 1985 mercury 25hp..need help please!!!! no spark now

Im 15 years old and my AWESOME dad gave me a 1985 25hp XD Mercury. I had multiple problems with my motor. I fixed it by myself because my dad in disabled. I found the same problems that you have had. I found out that my timing was off and my spark plugs/wires went bad. I have discoverd that three websites have everything you need to rebuild every part of the motor like I had to do. I had to rebuild the carb aslo. No the boat runs like new. The three best sites that i have found to buy the parts are...

1 - www.iboats.com
2 - www.crowleymarine.com
3 - www.bradfordmarine.com (have serial num handy) located beside boat mount.

Also for alittle advice, get a manual. Heres the site.

http://www.clymer.com/Book.aspx?bid...tboards+(Includes+Electric+Motors),+1972-1989