4.3 LX merc frost plugs?UPDATE!!

[mattie_k]

I've got a 1996 Bayliner capri with the 4.3LX in it and was wondering, are the frost plugs the things that you can see just above the oil pan? I just reattatched the water lines and went to fire it up in my yard (with the hose on of course) and about 10 secconds after it started I noticed water dripping from underneath the motor, so I quickly shut it down. Upon further inspection I saw a "bowl" like disk in the bilge and found where it came from on the block and carefully re-inserted it. Fired up again and no drip and seemed to be running great, I hadn't even put the new plugs in! <br />I guess I was wondering if that plug being blown out over the winter means that the block is cracked? Any thoughts or experience would be great!

 

[Bondo]

Re: 4.3 LX merc frost plugs?UPDATE!!

Roll the Dice,............ At this point, It's 50/50..........

 

[tommays]

Re: 4.3 LX merc frost plugs?UPDATE!!

there real use is to remove the sand core when the block is cast<br /><br />the fact that one came out means it was not drained correctly for the winter<br /><br />if your not getting water in the oil or haveing other problems count your self as very luckey and drain everything correctly next winter<br /><br />that means block ,manifolds,rises ,hoses ,ps coiler the works<br /><br />tommays

 

[WillyBWright]

Re: 4.3 LX merc frost plugs?UPDATE!!

Methinks you thought the block was drained, but sand/rust blocked the drain and prevented a full drain-out. You need to probe the holes to make sure it all comes out. Best of luck.

 

[mattie_k]

Re: 4.3 LX merc frost plugs?UPDATE!!

Well, I haven't run the boat yet to see if I'm getting any oil in the water but after letting it idle up to temp the oil is still clear. I also checked around for cracks and couldn't see any so hopefully.....we'll see i guess!<br /><br />If it is cracked maybe a 350 next time?!?

 

[marinemech1]

Re: 4.3 LX merc frost plugs?UPDATE!!

mattie: don't those horseshoes up your a$$ give you hemeroids??

 

[mattie_k]

Re: 4.3 LX merc frost plugs?UPDATE!!

So I thought a trip to a smaller local lake would be a good idea for a "shakedown" of the boat, here's what happened. <br /><br />Started fine at the dock, I let it run up to normal temp then shut it down and checked the oil, looked good no water there! No visable external leaks so off we go! Its a small lake with the public ramp at the north end and about a 1 mile no wake zone past houses until you hit the main lake area, so I set the rpms at 1500 and cruise out the the marker bouy. At the marker I again shut it down and do my oil/visual inspection of the motor and all still looks good. Fire it up, no problem, into gear and away we go. Get up on a slow plane (17mph/2600rpm) gauges look good out into the middle of the lake turn around and head back in the direction of the marker bouy add some rpms(3300-3500) and still seems to be running quite well. I get to the marker bouy and cut the power, put it in neutral and kill it then the damn thing diesels for about 5 seconds then backfires though the carb! <br />It has run on before but that was only after long periods of skiing on very hot days and was never a real problem as for the backfire I thought it might be from older gas still in the tank...<br />So I do my checks, oil looks good, no leaks visable yada yada... then I go to fire her up and the thing doesnt turn over!!! Starter engages, motor turns about a 1/8th of the way then slamms to a halt, not pleasant.<br />Paddle back to the ramp (downwind thank god) load her up. Back home I start to pull the spark plugs and the second one drips out water (port side, middle plug) how did that get there? Would water in the cylinder cause the motor to not turn over?<br />Any hoo, could it be the exhaust manifold letting water run down and enter the cylinder, or maybe the head is cracked is what I'm thinking. I live about a 3 hour drive to the nearest Mercruiser service center so I'm hoping to figure this out myself and hopefully do the work here. <br />Anyone have this sort of problem before?

 

[rodbolt]

Re: 4.3 LX merc frost plugs?UPDATE!!

if it dieseled before shut down it could have pulled water from the exhaust into a cyl. yes water in a cyl will lock the motor. remove the plugs and spin it over with the stop lanyard in the off position. reinstall the plugs and retest. then ya gotta find and correct the diesel problem. water in a cyl is normal after a run on condition. the run on is not normal.

 

[mattie_k]

Re: 4.3 LX merc frost plugs?UPDATE!!

But what could it be? Timing, Vaccum leak, dirty carb...?

 

[Don S]

Re: 4.3 LX merc frost plugs?UPDATE!!

Could be lots of things, spark plugs, timing, carb, idle rpm too high, even shutting down the engine after a run without letting it idle for a minute or so. Especially if the idle is a little to high.<br />Here is a Mercruiser service bulletin about water intrusion. <br />(Especially page 5, the part about water injestion)<br /><br /> Water Intrusion

 

[jeff13601]

Re: 4.3 LX merc frost plugs?UPDATE!!

That boat tossed the frost plug somehow. I hope its not anything serious. Was the boat winterized last year?

 

[mattie_k]

Re: 4.3 LX merc frost plugs?UPDATE!!

Wow Don, great link! That makes me think that I didn't let it idle long enough before shutting down. I'm going to put the exhaust manifolds and risers back on and give it a complete tune up, I really do think that the timing is a bit off. Thanks Don!<br /><br />Jeff, I did winterize the boat last year but some sand must have blocked the one drain hole and hide some water in there. I'll know better to really probe the holes next time.