I've been banging my head on a starting issue with the outboard motor mentioned in the subject line (it's a manual pull-start).

Problem is that when I pull it over, it doesn't sound/feel like it even attempts to pop.


  1. Full, nice spark on new plugs gapped correctly on both cylinders
  2. TDC is properly zeroed out between flywheel and timing pointer on cylinder 1 (although I don't have a timing light currently, this should be close enough to at least fire the cylinders). This, to me rules out a broken flywheel key
  3. There's definitely fuel being delivered (carb is brand new) (I've even tried manually misting the intake directly). I've also intentionally flooded the engine to verify that carb is delivering fuel)
  4. The engine is not flooding under normal starting conditions
  5. Air vent on the external fuel tank is open and working
  6. Primer bulb and fuel line from the tank are new and operating correctly
  7. I have verified that there is no "safety" feature grounded
  8. Fuel inside of the cylinders does burn to some extent, as if I crank the engine over a few times and quickly pull out the plugs, I get a slight bit of exhaust fumes come out of the plug hole
  9. I have verified that the proper coil is connected to the proper cylinder
  10. Everything is lubed up properly, engine has absolutely no leaks at all (it's exceptionally clean actually)

The only thing I haven't ruled out is the engine compression (as I no longer have a compression tester).

My question is whether this sounds like it could be compression or not. If so, I'll go buy a new tester and go from there (that said, at least when turning it over, it feels like the compression is good, but I know that's not a valid test).

If compression doesn't seem like a reasonable problem, any other ideas what it may be?

Since I just recently acquired this motor from someone else (you can keep it if you can fix it), I'm speaking only of cold-start here, as I've never been in the presence of it when/after it's already been running. Temperatures yesterday while I was working on it were approximately 13C.

  • 1
    Welcome to Motor Vehicle Maintenance & Repair! Are you sure your plugs aren't fouled out at this point? It sounds like there is an abundance of fuel, which if it's fouled the plugs, you won't get anything. You don't state whether it has an electric start or pull start? If pull start, you might try putting an electric drill (or impact set on high torque) to the main crankshaft nut to get it to spin faster and more consistently. This would wear you out less and provide more rotational speed to get the engine to start easier. First, though, get your cylinders completely cleared. Commented Mar 30, 2019 at 15:39
  • Thanks @Pᴀᴜʟsᴛᴇʀ2, plugs definitely aren't fouled (brand new actually), and looking into the cylinders through the plug hole with a flashlight, the cylinders/top of pistons are very clean (and dry) as well. Only time I flooded it, I did it intentionally just to ensure that I had proper flow. It is a pull start, and today I did already have planned to throw a drill onto the crankshaft as my arms are killing me from 500 or so pulls yesterday. I also left the plugs out last night just to try to air out any residual fuel from them, and the cylinders.
    – stevieb
    Commented Mar 30, 2019 at 16:00


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