2000 4.3L Mercruiser hydrolock

[tommy8604]

ok well ill start from the beginning. Last year i bought a 2000 Bayliner Capri with a 4.3l Mercruiser, the motor was bad at that time but i like to buy broke things to get cheap and fix myself (learn more about it that way). So i bought a used motor and put in it and used everything off the original motor besides block and heads. (never removed the first head bolt). So we completed the motor swap and it fired right up and ran perfect besides needing a little timing and carb adjustments. So we got two boats just in case and took it out and it ran perfect. so the next day i thought it did so good that we would just take it out, well we started kneeboarding behind it and at the end of the day go to leave and it wont turn over. so i thought from all the starting and stopping the battery was low. finally limp it back and charge the battery and rebuild the starter. take it out again and it does perfect again so i thought that fixed it. so over the weekend we all go boating and run it for a good 6 hours and its starting to get dark so go to leave and what do you know it wont turn over again and we were tubing behind it this time so i thought it was the battery going bad. pull it in and charge the battery and still wont turn over. so i pull all the spark plugs and start to notice they are wet. all this time the oil level never changing and no water showing on stick. so i pull all the plugs and the right side of the motor has quit a bit of water in it and the left side just had a little. so i turn it over and it cranks over just fine now so i solved that problem but now how is the water getting in there and hope like #&!! i didnt bend the valves.

Im pretty good when it comes to motors so im doing all this work myself. but im hoping and preying that its blown head gaskets. what im asking is what are yalls thoughts on this? Do you think i may get lucky and get away with head gaskets or is it going to get deeper in my pocket (boy i hope not). so im not real sure on how these exhaust on these inboards work. i know that have water flow in them also so could it be in them, the intake, the heads, gaskets?

sorry for making this so long but i know when asking these questions the more info the better

Any advise will be greatly appreciated

Thank you

 

[90stingray]

Re: 2000 4.3L Mercruiser hydrolock

Exhaust manifolds have cooling water flowing around the exhaust in different passages. When the manifold becomes rusted thru it allows cooling water into the engine cylinders... thus a hydrolock. What kind of exhaust manifolds do you have? Are they a large one piece design...or do you have a manifold with a riser bolted ontop and elbow at the rear... all clamped together? Either way you should pull and inspect. If you need to replace everything expect $500+

 

[tommy8604]

Re: 2000 4.3L Mercruiser hydrolock

I have the two piece exhaust manifolds. with the square top that elbows off of it. When i bought the boat either the heads or the block was cracked and rusted the inside of the motor. my theory is that the previous owner didnt know much about boats and never winterized the motor and i was thinking i could just get away with a used long block but i guess not and now im thinking that when it wasnt winterized it may have cracked the exhaust manifolds too.

 

[RiggerMark]

Re: 2000 4.3L Mercruiser hydrolock

evening,
i just brought me another "broke" boat.... anywho, i'd probably do a compression test first, easy anuff, if that all looked good, next guess would be the exhaust flappers, i believe you have one on each side of your exhaust y, sounds like they get rusty and sometimes fail, hopefully one of the old salts here will chime in and sit us straight, hope it's a cheap and easy fix.........Mark

 

[RiggerMark]

Re: 2000 4.3L Mercruiser hydrolock

just saw your post as i posted, the manifold leak test in the stickys works great, have use it a few times now, i save the acetone for reuse, mine were hair lined cracked, and with the 4.3's being so pricey, i cut nice little micro channels where the two cracks were, then had a shop weld it up good, cost me around 40 bucks, and has at least 50 hrs. on it with no probs, that was with omc, maybe merc exhaust is a lot cheaper, i would of liked to replace mine, but i've got to watch the money when it comes to boats or the wife will............... you know................hope it goes well..............Mark.... seems like the compression test would tell ya about ya gaskets too......

 

[tommy8604]

Re: 2000 4.3L Mercruiser hydrolock

i was hoping for a cheap fix but that hope is fading lol. but on this boat there are no flappers on the back of the boat but exits in the outdrive. unless there are flappers on the inside somewhere. like i said i dont know alot about the exhaust on these but know they are cooled by water and the water exits with the exhaust but dont really know much about the internals of them but about to start learning it looks like. As for a compression test, im going to do that tomorrow. it got dark on me tonight and wasnt about to get that done but now that its been brought up its pointing at the exhaust manifolds do to prior owner not winterizing it and once the motor went bad he just sold it and i picked it up for $2000 so even if i have to put exhaust on it im not sitting too bad in it but a cheap easy fix is always nice.

 

[joewithaboat]

Re: 2000 4.3L Mercruiser hydrolock

I'm betting you have rotten, rusted trough or cracked manifolds.

 

[Struc]

Re: 2000 4.3L Mercruiser hydrolock

Here are some cheap exhaust manifolds & risers:

http://www.perfprotech.com/store/pr...iser-43L-Painted-EK-MERC-43L-NC-NS,75395.aspx

They are HGE brand, which get mixed reviews. They seem built OK, but are made in China. I bought them for my boat, so we'll see how it goes this summer. They run about $500 after shipping. A lot of people recommend just going OEM, but I think the cost is nearly double what I paid.

There are flappers in the exhaust "Y" pipe in the back.

$2000 is a great price for that new of a boat. Even since you had to replace the engine, you'll still be well under its value. I'm just finishing up an engine swap on my boat - bought a used truck engine and threw all the marine parts on.

Post up some pictures of your bargin find! Everyone here loves pictures.

 

[tommy8604]

Re: 2000 4.3L Mercruiser hydrolock


First time taking it out


New motor going in


Old motor coming out


New motor in


The old motor i took out

 

[tommy8604]

Re: 2000 4.3L Mercruiser hydrolock

[video]http://s686.photobucket.com/albums/vv222/tommy8604/?action=view&current=IMG_0339.mp4[/video]
starting the motor for the second time

 

[tommy8604]

Re: 2000 4.3L Mercruiser hydrolock

Well i did a compression test on all the cylinders today and they all come back at right around 150. so after that i pulled the exhaust manifolds off and looked at them real good and then took them apart. well to me the manifolds look fine, no real bad rust or obvious cracks. but the gasket in between the upper and lower exhaust manifold was in very bad shape. you can see all the gasket between the water ports and exhaust ports was torn came apart. i know i may be counting my chickens before they hatch but im pretty sure this gasket is my whole problem. im still going to do the acetone test on them but i think i got lucky here.

 

[90stingray]

Re: 2000 4.3L Mercruiser hydrolock

The first pic looks like there is a crack on the upper portion. Granted it's from the water jacket outward. But there could be more cracks that you can't see. But If the block was cracked from frozen water... i would imagine the manifolds would be cracked too. They have rust spots inside the exhaust passage which says that there is water present. But check them and report back.

 

[tommy8604]

Re: 2000 4.3L Mercruiser hydrolock

tomorrow im going to try the acetone but didnt have time again tonight. but i did go back and look into that crack that shows up on the picture, it is part of the gasket that was left behind. once i scraped the gasket off the was no crack. but yes there was definitely water in the exhaust port. when i removed the manifold water came out of the exhaust ports so i think im on the right track as of where the water is coming from and im still hoping its just the gasket in the pictures that was all that was leaking but ill test them and look into the flappers tomorrow.

 

[achris]

Re: 2000 4.3L Mercruiser hydrolock

With the elbows off you should see the exhaust shutters....

 

[tommy8604]

Re: 2000 4.3L Mercruiser hydrolock

well took my boat to the lake this weekend. got my gaskets and every thing. cleaned the surfaces on them real good for a good seal and got in the boat to put it all back together and decided well let me check the flaps real quick and found out both of them were bad. so now its back to ordering some more parts. so maybe by next weekend i can finually put the boat back in the water again.

Thanks everybody for all the help. i would have never know about the flappers.