5.7l a1g2 crank ran backwards

[AShipShow]

Hey guys... I'm I'm the middle of my 96 bayliner restoration. I got the boat last summer and promptly pulled the drive and motor to start on ripping everything out (floor, stringers, transom, etc). Been sitting covered since and today I needed to hoist it into the boat to mark and measure for the new front mounts and decided to try and fire it up...

I hooked the battery positive to the starter post, negative to the block. Hooked up the garden hose to the inlet hose. Hooked up the fuel line and ran itto a 5gal gas can. Then made a jumper harness to connect 5 and 6 on the harness plug and touch 7 to start it. All went well and it started pretty easily.

I let it idle and warm up for a few minutes. After I was happy with it, I shut it down by removing the jumper from the harness plug...
then I noticed as the coupler stopped, it actually made a couple revolutions back in the reverse direction before completely stopping.... this freaked me out cuz I thought it might have sucked water back into the cylinders so I ran it a few more times and each time I stopped the motor it didn't do it again. The only other thing i can say is it sounded like it might be running lean.. it stumbled a little when giving it some throttle and even shot apuff out the carb once.

thanks in advance...

 

[Rick Stephens]

That'd get me worried. Not sure you need to worry about it after the steps you took. Kit the carb and call it good.

 

[NHGuy]

What happened was probably shutdown dieseling. It occurs when there are hot spots, too much timing or water in the combustion chambers.
I had this condition on my previous boat and I could manipulate it by running the engine above idle for 30 seconds before pulling back to idle and shutting down. I'd also throw it into gear during the shutdown to help halt the engine's spinning.

The engine in my boat had failed exhaust manifold water jackets and would get water in the chambers at idle. This raised the compression ratio by taking up some of the space intended for air and fuel. The higher compression mixture would detonate without spark or diesel.
The fact that your engine did it once and then not again is encouraging. But if it happens again we can help you with tests to lead to a repair.

 

[AShipShow]

Could hot spots be from a lean condition? That was my assumption on what was happening and after running a few more times and revving I'm wondering if some of the gunk in the carb cleared out and that's why it didnt do it again... thinking a carb rebuild wouldn't hurt anyways.

 

[Rick Stephens]

I'd kit the carb just because it sat for a few years and dried itself out. Bet you find crystals in it.

 

[AShipShow]

Kit on order.. I also ordered a new float as I've heard they can absorb fuel over time... Hopefully that resolves my issues... Will report back after rebuild.