197?'s 4HP Merc won't start

Craig W

Petty Officer 3rd Class
Joined
Oct 29, 2003
Messages
84
Hi all, I'm normally over in the Yammy and boat building areas but a friend has asked if I could take a look at his 4HP Merc for him. Just searched and couldn't find much that could start me in the right direction. From what I've seen here, it looks like it's either early 70's or late 60's? it has blue stripes and SN# 7086213<br /><br />The situation:<br />-it seems to be getting fuel to the cylinders. After many pulls I feared I'd flooded, so I pulled the plugs to check. It wasn't firing, the plugs were wet (so I "could" have potentially flooded it). I cleaned and dried off the plugs, let things sit for a bit and tried again to no avail. Due to the "wet" plugs, I'm thinking it's safe to assume fuel is getting where it should<br /><br />-so is it likely I'm not getting spark? silly question, but what would be my best way to check?<br /><br />I noticed in one post that it was mentioned that the coils and condensers have a tendancy to go bad on these engine? I don't have a manual for this engine. Can anyone provide me with some info for testing them?<br /><br />Are there any other thoughts as to what (and how) I can check for anything else to work thru a process of elimination in an attempt to get it running?<br /><br />thanks in advance,<br />Craig
 

Paul Moir

Admiral
Joined
Nov 5, 2002
Messages
6,847
Re: 197?'s 4HP Merc won't start

Unfortunetly I have no way of figuring out which year your merc is, since that's a Canadian serial number, but you mention 'cylinders' so I presume this is a 4hp GNAT, the only 2cylinder 4hp outboard mercury ever made as far as I know. Have a look here and see if it looks the same. Click 'Mercury' then '40, 4 (GNAT)' then your serial range.<br />It should only have forward and neutral.<br />GNAT's were only made from '79 to '81 I believe. They have CDI ignition with no points or condensors. The ignition coils seem very reliable, and it's unlikely both are fried. :) <br /><br />To test for spark, unplug one of the sparkplug leads, and insert a screwdriver that fits. Hold the screwdriver 1/2" away from something metal on the engine and have someone else pull the starter. You should get a bright strong spark.<br />If you don't get spark, disconnect the kill switch (One of the orange wires going to the powerpack on the side of the engine) and try again. If the engine starts, you'll have to choke it to stop it.<br />Another thing is to closely examine the wires, checking for deteriorated insulation.<br /><br />I've still got some notes from when I fixed up my brother's GNAT some time ago. There's nothing in them relating to ignition, just timing, and torques, but if you want them email me at paul.moir@ns.sympatico.ca. You can order manuals from Iboats, or sometimes you can borrow one from the local library. <br /><br />PS - go very easy on the pull start. It's very delicate and costs $80CDN to replace!<br /><br />Hope this helps!
 

Craig W

Petty Officer 3rd Class
Joined
Oct 29, 2003
Messages
84
Re: 197?'s 4HP Merc won't start

thanks for the reply Paul. It seems to be a GNAT (4hp 2cyl CDN version). It does only have FWD and Neutral directions, AND a plastic prop to top it all off!! The information you've provided is appreciated. It will give me some direction to proceed -now I only need to find someone to pull start it while I watch for the spark (hehe, I'm aware of the ol' screwdriver trick, I guess I was just hoping there may have been some way I could have tested things "solo" ;) ) I'm sending you an email. Any further information I can get on this "cute" little thing may come in handy at some point while I try to get it running.
 

Paul Moir

Admiral
Joined
Nov 5, 2002
Messages
6,847
Re: 197?'s 4HP Merc won't start

The best way to do them solo is with a spark tester. I don't think Canadian Tire sells them, but any other auto place should.<br />Princess Auto has them, if they're near to you. They call it a Spark Gap Tester. There's one in London, Kitchner, Hamilton, Mississauga, etc.<br />Good luck!
 

andrewkafp

Lieutenant Commander
Joined
Mar 15, 2003
Messages
1,668
Re: 197?'s 4HP Merc won't start

I reckon it's a 1976 Canadian motor.<br />Reason..<br /><br />Serial Group chart that I have shows<br />USA 4357640- 4576236 = CAN 7056998-7088579 = Eur 9107214-9136249<br />The Dougrussell site shows CAN 7085673-7146487 = EUR 9075839- 9256980 http://www.marineparts.com/partspages/techhelp/tech14.htm <br />It seems to be as Paul stated.. A 1976 GNAT 2 cylinder. The European number is listed there which will line up with yours.
 

Paul Moir

Admiral
Joined
Nov 5, 2002
Messages
6,847
Re: 197?'s 4HP Merc won't start

Geeze, Unicorn, that reminded me of something:<br /> Merc 4hp info <br /><br />Makes it a 1978.<br /><br />There's a bunch more here. But no Australian numbers yet!
 
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