Outboard tech's opinion requested / merc 9.8 wont run

[FZ1]

1969 merc 110 (9.8) will not run.

I'm not new to engines at all. I've repaired my fair share of Auto/Motorcycle/Marine over the years. I'm pretty much aware of what it takes to get things like this working. I've worked on everything 2 or 4 stroke, 1,2,3,4,5,6 and 8 cylinders. Points and condensers, reeds, piston ports, and carbs to Digital electronic ignition, fuel injection and 5 poppet valves per cylinder. So, I'm not a newbie. But I think I'm missing something with this outboard I've been messing with for a little while....

Carb is clean (yes i know how to do a cleaning) and will flow fuel with air passing through venturi. Idle screw set at 1.5 turns out as a starting point
Compression numbers are 100 or so with a crappy borrowed push on type of tester (not good but within 10% of each other)
Spark is present on new b7hs's just laying on engine ground
Makeshift spark tester failed to spark much more than plug gap
Eyeball timing of points opening indicates approximate TDC at idle
Points gapped at a tight .020
Reed valves are not stuck. if piston is placed with ports open and compressed air is blown into carb, a nice fuel mist shoots out of the spark plug hole.

I got this motor with a spare ignition plate with coils and flywheel unattached, and one coil missing on the original. Owner claimed it was a theft recovery. I think he just messed around with it and gave up. I've never met an engine that I couldn't at least get to start. This one,... using all my tricks (tho I'm no genius or marine tech) wont even fart for me. Not even with ether sprayed into the cylinders/carb and plugs screwed right in and rope pulled like a raped ape!.
I even went so far as to pull the flywheel off (AGAIN) and swap one set of (old)condensers with another (old) set. Not one single burp fart or snort. I dont think its possible to get timing 180 degrees out, but i tried switching plug wires too .

I've got a sierra tune up kit on order, I hope its just bad capacitors causing all this trouble, not a crank seal. Possible 9.8 parts motor for sale next week

Who's seeing what I missed? Hmm? any ideas? please no "dont use starting fluid" threads. I fogged the crank bearings before attempting that.

 

[Starppy]

Re: Outboard tech's opinion requested / merc 9.8 wont run

It almost has to be spark. Put the tune-up kit in it with new condensers and points and then give it a try.

The other possible thing is that you mentioned that one of the coils was out when you got it. It's been a while since I worked on the small ones, but I do remember that replacing/mounting the coils was a pretty finicky job and had to be done just right or you wouldn't get a spark. I don't remember the procedures. Do you have the Seloc or Merc service manual by chance?

Unfortunately that's all I got. Sounds like you covered ddarn near everything. Good luck with it.

 

[James R]

Re: Outboard tech's opinion requested / merc 9.8 wont run

It may be a little obvious but you didn't mention the choke.
These motors need full choke to get the crankcase filled with fuel mix and only then will they fire.

 

[FZ1]

Re: Outboard tech's opinion requested / merc 9.8 wont run

Thanks Starrpy:

Bad news. New points and condensers didn't change anything except making a stronger spark (in air). I'm stumped. I don't have an inductive timing light so I can't say for sure that I'm getting timing right. The only other thing I can think of is leaking crank seals and its just sucking air from there instead of through reeds/carb but I find it hard to believe I can't get it to fire at least once, even using ether.

What am i missing? Anybody?

 

[CharlieB]

Re: Outboard tech's opinion requested / merc 9.8 wont run

I'm not convinced that you have enough spark, yet.

Rig a 2 X 4 with 2 nails 1/4 inch apart, attach the plug wire to one and ground the other, will that spark? Bright blue 'crack'?

The Ignition coil air gap to the flywheel is critical, too large and you get a weak spark, ANY contact and you get NO spark.

Also, what gap do you have on the spark plugs? .035 is too large, start closing the gap to .025

 

[Faztbullet]

Re: Outboard tech's opinion requested / merc 9.8 wont run

It sounds as if you have weak coils, as it will fire out of cylinder but not under compression. If that has the 2 coils a old merc or johnson shop with the merctronic/stevens tester can test the coils . If not new are about $70 ea. If the model you have has a stator ring the stator could be weak.

 

[FZ1]

Re: Outboard tech's opinion requested / merc 9.8 wont run

Wow you guys are really good and helpfull. I never thought of the coil air gap, this is an old style 2 coil system, and as delivered, there must be at least a 1/4" air gap between the (armature?) metal part of the coils and the magnets. The windings (in black plastic) are held on to this with a little spring clip. I just assumed everything would be automatically spaced. There is no way to move the armature closer to the magnets of the flywheel. The only way to set the coils closer to the spinning magnets is to slide the windings off of the locking springs detents. That can't be right.

As for a 1/4" big thick snapping healthy spark from improvised tester? Not happening. I'm thinking new coils, but I really did not want to sink any money into this motor (who ever does lol)

Thanks for the help Gents. Any other ideas would be welcomed of course. I wish I had a site for downloading manuals for outboards that was as good as the one I have for motorcycles! if you need any motorcycle manuals just e-mail eff_jay12@hotmail.com for url to free website.

 

[CharlieB]

Re: Outboard tech's opinion requested / merc 9.8 wont run

I got this motor with a spare ignition plate with coils and flywheel unattached

MEthinks you have mismatched parts, that flywheel is NOT the one for that motor.

Post the model and serial # of your motor.

Hopefully someone will have its sister and be able to post a measurement of the inside diameter of the flywheel.

The coil to flywheel airgap should be closer to .030 or less.

 

[FZ1]

Re: Outboard tech's opinion requested / merc 9.8 wont run

1969 merc 110 9.8hp ser # 2622719 Canadian motor
there is 239-4173 stamped on the underside of the flywheel
pictures attached.

Rough measurements are 5-1/4" between the magnets and almost the same between the hard parts of the coil. I've tried to show everything as best I can. Do I have the wrong flywheel?

 

[CharlieB]

Re: Outboard tech's opinion requested / merc 9.8 wont run

I haven't been able to locate this serial # on the Merc site, but I have seen this motor and problem before.

Check the white plastic part/wire terminal for the coil and condenser. Look for signs of carbon tracking to ground, under compression the voltage goes high enough that electricity takes the path of least resistance, arcing to ground alongside the plastic from the terminal pass-through to ground instead of arcing at the spark plug.

If these plastic parts are NLA then carefully sand off ALL signs of the carbon trails, clean with alcohol, reinstall and retest for 1/4 inch spark.

 

[rtpassini]

Re: Outboard tech's opinion requested / merc 9.8 wont run

wow. thats a lot of debunking. good luck to ya.