Boat cranks and backfires but does not turn over

[Nelson C]

So I ran the boat out a couple weeks ago and I hit a sand patch and I tried to steer the boat away but as I was leaving the shallow area and I felt a sudden push forward for a second but after that the engine ran fine for about a minute or two which it then shut down and didn't start. I replaced the spark plugs and tested them with the spark tester and with the multimeter tested the coils I also removed the kill switch for testing purposes and had to manually move the starter up so it makes contact with the flywheel and spins. Now when I try cranking the engine it spins fast and leads to multiple backfires out of the exhaust. What could be going wrong or what should I try next?

 

[GA_Boater]

Well you know what motor you're working on. We sure don't know.

I know this isn't a boat resto question, it will be moved once you tell us what motor.

 

[Nelson C]

Well you know what motor you're working on. We sure don't know.

I know this isn't a boat resto question, it will be moved once you tell us what motor.

Ohh right sorry still kinda working out this forum stuff but it's a 1988 bayliner Capri with a 85 hp force (Mercury?) outboard motor

 

[MTboatguy]

Sounds like you might have busted a crank shaft between the piston journals, which is allowing a couple of the pistons to fire? Not common, but I have seen it happen before.

 

[Nelson C]

Sounds like you might have busted a crank shaft between the piston journals, which is allowing a couple of the pistons to fire? Not common, but I have seen it happen before.

Hey there! Thanks for the reply. I went out and checked it out and I had the spark plug wires reversed so I connected the red one to the middle coil and the orange wire that comes from the farthest (cd module?) I'm not sure the name of the box but the two boxes next to the coils I connected the orange one farthest away from the coils (had the orange and red connected to it) to the top coil and the bottom orange one to the bottom coil. Now she starts right up but won't spit water out of the two holes on the back so I gotta figure out the cooling problem which caused the overheat in the first place. Gonna check out the impeller and replace tomorrow maybe.

 

[MTboatguy]

Glad you found your firing problem, water pumps are pretty easy to change, just make sure to pay attention to the instructions and it should go smoothly.

 

[jerryjerry05]

If you injested a bunch of sand???
Then when you have the lower unit off.
Hook a hose to the pickup tube and start the motor and run it.
Try to flush the gunk out.
Also while it's running tilt the motor up and down.