1996 4.3 volvo penta - I think it is seized - need advice

[arriva2450]

I have a 96 boat with a 4.3GL volvo penta carb inboard/outboard. It has been giving me problems for the last year, where after it warms up the motor would start to bog at WOT (it would start great, idle great, rev great and run great at WOT for the first 10 mins). When it started to bog it would gurgle and backfire too. I found that if I let it sit for 30 minutes or more that it would then work fine again until again after 10-20 minutes and would do it again.

I replaced the fuel pump and fuel pump relay which made no difference. So I pulled a plug and saw signs of lean so I checked the air mixture settings. I have a holley 3520 2 barrel carb and googleing said the screws should be about 1.5 turns out each but found mine to be 1 full turn (hence lean) - so I turned each to 1.5 out and went for a test run. After a few minutes it started to bog again so I turned it off with the intention to further adjust the air mixture - this time the engine dieselled (continued to run with ignition off) for about 10 seconds until it shut off (never did this before). I then tried to restart but no turn - just click. towed it to shore and tried again - still just click. Got a breaker bar on the crankshaft nut and it isn't budging in either direction. So I removed each of the plugs and found that water came out of the middle plugs on both the left and right side???? So with the plugs out I tried the starter and again just click and tried the breaker and still can't budge it.

So first obvious question, what causes water to pour out the 2 spark plug holes? Could this have been due to the dieselling? Or have I had another problem for a while causing water to get into the engine. BTW - I checked the oil and it is perfect (no signs of water).

Next question - is there anything I should try to restore the engine, or is it a goner. I did spray a little penetrant into each cylinder today and will try again tomorrow, but doubt that will make a difference. I'm thinking of removing the starter tomorrow and trying to force turn it from the flywheel - but again would appreciate some feedback or advice based on my symptoms if I am wasting my time, and what caused this.

Thanks

 

[Scott Danforth]

first, the idle mixture screws only affect idle. the remainder of the carb passages are what control mid-range and WOT

second, when your motor was dieseling, it was most likely running backwards sucking in water. Hence the hydrolock. this is one potential source of water ingestion

third, NEVER EVER EVER try to turn a GM motor by the crank nut. you will never turn the motor and you will strip out the end of the crank. then you really need a new motor

4th, you were hydrolocked. get the motor running ASAP to dry it out or it is a goner. with check your starter connections. if you let it sit for any length of time more than a few hours with water in the bores, you may have rusted the bores.

5th, look at your exhaust. if you boat in salt water, you pull the manifolds every few years for inspection. the fact that it was constantly bogging would lead me to believe that your exhaust has been leaking for a while.