Mercruiser 4.3LX Alpha One won't start

[imjuspiayin]

Hello,

I have a 1994 Baja Islander with a Mercruiser 4.3LX Alpha One motor. I recently boat this boat used and it is cosmetically in excellent condition. The engine also looks great. Yesterday was our first time really taking it out and it was running great for about an hour. We hit a large wake and the boat then shut off. When I now go to start the engine there is a loud knock sound and the engine will only turn a tiny bit. The starter also jumps when I try to start it. The oil level is good, there is no oil leaking out from anywhere, all belts seem fine, and I cannot see anything wrong with a quick look over. I just checked out all the paperwork for the boat and noticed that the owner had the starter and gimble bearing replaced twice on this boat so I am wondering if that is what the problem is. I am not very familiar with boats and was wondering if anybody had any advice for me or anything I could try before I pull it out and bring it for service. Thank you!

 

[searay3]

Re: Mercruiser 4.3LX Alpha One won't start

Sounds like water intrusion in the cylinders. you need to pull the spark plugs and turn it over. You need to do this right away. If it's salt water, and it sat any period of time, you could already have damage. Watch for water spurting out of the cylinders.

 

[imjuspiayin]

Re: Mercruiser 4.3LX Alpha One won't start

The boat is in freshwater so hopefully there is no damage if it is water intrusion. I will immediately pull the plugs and turn it over. When you say turn it over do you mean by hand or with the starter? Is it like a car where the engine can get hydrolocked and be destroyed? Also, if there is water, what would the next step be? Thank you for your help....it is much appreciated.

 

[imjuspiayin]

Re: Mercruiser 4.3LX Alpha One won't start

Ok so as soon as I took the spark plugs out, water poured out. How does this happen and what would the next steps be?

 

[Dukksoup]

Re: Mercruiser 4.3LX Alpha One won't start

spray storage seal in the cylinders or wd40 works also, which cylinders had water coming out? I have the same engine and just went thru this 1 month ago. Do you have engine run on when you shut the boat off at all? Or could possibly riser gaskets

 

[nola mike]

Re: Mercruiser 4.3LX Alpha One won't start

Ok so as soon as I took the spark plugs out, water poured out. How does this happen and what would the next steps be?

next step would be to turn it over till dry, replace plugs and start engine. after that, check the flapper valves in your exhaust. sounds like when you hit the wake you had water backflow through the exhaust...