4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

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xadiohead

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

Do you think this test would help narrow it down to the one piece exhaust manifolds: since boat is locking up after hours of sitting, if it is bad one piece exhaust manifold(s), i think we are presuming the water is slowly leaking from the riser part into the exhaust manifold part and then into a cylinder with an open valve. So couldnt I run the engine, immediatley drain the manifolds, and try to start it the NEXT day? If i did this a couple days i would think this would help narrow down the problem depending on whether the engine still locked up. Idea here is that once i drain the manifold, there will be no water to leak back into cylinder if that is whats happening.

What do you think?
 
Bondo

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

xadiohead said:
Do you think this test would help narrow it down to the one piece exhaust manifolds: since boat is locking up after hours of sitting, if it is bad one piece exhaust manifold(s), i think we are presuming the water is slowly leaking from the riser part into the exhaust manifold part and then into a cylinder with an open valve. So couldnt I run the engine, immediatley drain the manifolds, and try to start it the NEXT day? If i did this a couple days i would think this would help narrow down the problem depending on whether the engine still locked up. Idea here is that once i drain the manifold, there will be no water to leak back into cylinder if that is whats happening.

What do you think?
Click to expand...

Ayuh,.... Go for it if ya wish,.... I'd just yank the manifold Off, 'n look for Rust tracks,....

The crack could be Anywhere in the manifold, not just at the top riser area,...

Btw,... a single drop of fluid should be enough for a smell/ taste test,...
 
MikDee

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

Those look like the wrong spark plugs? RS12YC? They look like "hot" plugs, compared to the recommended AC MR43TS.
 
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xadiohead

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

Bondo said:
The crack could be Anywhere in the manifold, not just at the top riser area
Click to expand...

But if I pull the drain plug on the manifold, aren't I essentially draining any water that could be leaking back into cylinder?
I don't have time this week to pull the manifold off and I have also read it takes two people.


MikDee said:
Those look like the wrong spark plugs? RS12YC? They look like "hot" plugs, compared to the recommended AC MR43TS.
Click to expand...

The manual I have "MerCruiser #25 GM V-6 262 CID (4.3L)" published 1999 list three spark plugs as options: AC - MR43LTS
Champion - RS12YC NGK - BPR6EFS

I had the same problem last week when I had the NGK BPR6EFS plugs installed.
 
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xadiohead

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

I further looked at the exhaust manifold bolts and I think my boat requires the engine to be pulled in order to replace the right one and possible both! The seat frame is pretty much flush with the manifold. Can't even get finger in to touch one of the bolts!

Look at this picture: https://www.dropbox.com/s/vredyzn47n3k6jj/2014-04-21 17.16.41.jpg


Not sure why I just realized this. I don't have near the resources, knowledge or time to pull the engine.

What a terrible design and what if the new manifolds are an inch wider, they won't even fit!

Beginning to hate this boat.
 
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xadiohead

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

I think i am going to have my carburetor rebuilt and hope thats the problem. Boat started fine yesterday so the problem is intermittent.
I guy quoted me $125 plus cost of repair kit to rebuild it. Is that fair? I watched a youtube video and it looked more in depth than i want to attempt. He also said he would "set it" for me.
 
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xadiohead

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

Man it's crickets in here!

I hate to start new threads so I will post another question in here hoping somebody will help me out....

I am also looking at replacing just my starboard one-piece exhaust manifold/riser. I THINK that side is the bad side and I can remove that manifold without having to remove engine. Completely understand I should be replacing both, but right now it is not feasible.
After looking online at manifolds, they appear to be interchangeable between starboard and port side...Is that true? I don' really understand how that is possible given then aren't semetric. I just don't want to buy one and it only be for the port side.

hopefully somebody can help me out with all my questions.
 
Bondo

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

xadiohead said:
Man it's crickets in here!

I hate to start new threads so I will post another question in here hoping somebody will help me out....

I am also looking at replacing just my starboard one-piece exhaust manifold/riser. I THINK that side is the bad side and I can remove that manifold without having to remove engine. Completely understand I should be replacing both, but right now it is not feasible.
After looking online at manifolds, they appear to be interchangeable between starboard and port side...Is that true? I don' really understand how that is possible given then aren't semetric. I just don't want to buy one and it only be for the port side.

hopefully somebody can help me out with all my questions.
Click to expand...

Ayuh,.... Folks have Jobs ya know, this is All volunteer responses,...

We've been tellin' ya How to Diagnose yer problems, 'n how to Fix 'em,....

If you don't like the answers, I donno what to tell ya,...

The manifolds a side specific,...
I'm not gonna help ya ruin yer motor,...

If ya don't have the resources, nor the abilities, I guess ya gotta hire someone that does,...

Ya need a New Full set of manifolds, 'n risers, as a Kit, to get rid of the bat-wings,...
If you wanta go a different direction,...
Good Luck,....
 
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dazk14

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

There should be no need to pull engine to remove manifolds.

They use bolts, not studs. The bolt heads are recessed in the manifold and they only need to back out enough to free them from the head, which is only about an inch, or so, and with the recess you should be fine.

You can slide the manifold up. You can have the manifold pressure tested if you wish for short money and you should inspect the water shutters if you get it apart. They need the water shutters and you can get splash back into cylinders during normal operation, never mind when stopping.

I have single handed those before and one tip is to mark a line indicating the depth the manifold outlet is buried into the rubber coupler, before you pull it apart. That way the bolt holes will line up upon installation.

Upon installation, start with the manifold outlet end and just get that end of the weight supported by the rubber couple. Here you don't want it to go in too far, just supported.

Now you can focus your strength holding up the other end and finding a single bolt that you can get started. Once you get it started you're home free weight wise and it's just wiggling the unit further down on the coupler end to get bolts in.

Obviously, you need all your bolts loaded before you re-install.

I'm not disagreeing with Bondo's suggestion. I may have 2 new batwing manifolds tucked away in the shop.
 
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xadiohead

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

Thanks for the info..... DAZk14: do you really have some manifolds I could buy? please let me know asap as I am about to pull the trigger.

I had a mechanic come help me today.

1) I bought a carb gasket kit and he uninstalled my carb and is rebuilding it. I am doing this because the carb is terribly hard to start after a week of sitting (takes a couple minutes) and also because the oil I drained really smelt like fuel. Hoping I fix both these issues.

2) He also helped me remove the starboard exhaust manifold. This is the easy one. The exhaust hole closest to the outdrive (#1 in picture) had a little bit of liquid in it. Wasn't a lot by any means, but I'm guessing this is either THE problem, or a part of it. Here are some pics I took a couple hours later so the water is gone: https://www.dropbox.com/sh/vy2lb74rm1xgdno/D9aapNr8fJ

Does that look like substantial rust that could be my problem? I'm thinking there shouldn't be any rust in there since it is supposed to just be exhaust gases unless the jacket broke?
He said he has a cherry picker and capability to move the motor over enough to remove the port side manifold. He said he would remove it and install new ones for $150. Seems like a heck of a deal so I'm going to let him do it.

I am about to spend ~$525 on manifolds (assuming DAZk14 doesnt have any). I need to make sure I buy the right ones.

Would these work: GLM Mercruiser 4 3 V6 Exhaust Manifold 3" inch Riser Elbow Set 99746A17 98504A3 | eBay

The side of my one-piece manifold says: 807293C-CF

3) He is then going to remove/install water circulating pump and replace missing thermostat.

4) Total labor will be $125 (carb)+150(manifolds)+75(pump,therm) = $350.
Parts should be about $525(manifolds), $50 (carb gaskets), $90 (water pump), $35 (thermostat) = $700

That puts me at about $1050 I will be investing into this old boat. I really really hope this fixes the problem.

Please let me know any thoughts you guys have.
Thanks!
 
Watermann

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

You should really add one more thing to your list, a water pump kit for the lower unit.
 
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MarkSee

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

xadiohead said:
I am about to spend ~$525 on manifolds (assuming DAZk14 doesnt have any). I need to make sure I buy the right ones.......Please let me know any thoughts you guys have.
Click to expand...

You're going to all this trouble and expense and you're wanting to buy what some experts will say is possibly the worse manifolds you can....check out post #2 here where Chris lists the order you should be buying: http://forums.iboats.com/mercruiser...er-interchangeability-644906.html#post4559588

Mark
 
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xadiohead

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

Watermann said:
You should really add one more thing to your list, a water pump kit for the lower unit.
Click to expand...

I had a new impeller installed before last season. I've been good about not running engine without water so I think I am going to wait a year on that. Well at least until I have all this stuff done and know my boat works.


So I just did my own water leak test on the manifold I pulled. Please confirm that this proves the manifold is bad: I filled it up with water through the small hose. I blocked off the other end, but just used aluminum foil connected via duct tape, so not a 100% seal by any means. I just wanted some restriction. I then blew (nothing major) through the small hose and water gushed out all three of the exhaust holes. Is that proof? Thanks
 
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xadiohead

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

MarkSee said:
You're going to all this trouble and expense and you're wanting to buy what some experts will say is possibly the worse manifolds you can....check out post #2 here where Chris lists the order you should be buying: http://forums.iboats.com/mercruiser...er-interchangeability-644906.html#post4559588

Mark
Click to expand...

Thanks for the info. I know I will get shrugs for this, but I can't justify using eom parts on this old boat. I did find some Sierra manifolds. They are about $40 more which isn't a big deal if they are better. I do like how it says they are made in US
Mercruiser Marine Boat Exhaust Manifold Kit 4 3L V6 99746 44354 1985 2002 New | eBay

Can somebody please let me know if these are okay?
 
Fun Times

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

xadiohead said:
I blocked off the other end, but just used aluminum foil connected via duct tape, so not a 100% seal by any means. I just wanted some restriction. I then blew (nothing major) through the small hose and water gushed out all three of the exhaust holes. Is that proof? Thanks
Click to expand...
That might not be the best test to try!!!

If the water came up to the top of the (4) manifold holes, and you didn't seal the holes well enough from getting into the center hole and you blew air into the water jackets, I would have a hard time believing/trusting that you did not just blow water into the center of the manifold which will allow you to see water come out of the exhaust holes.

See if this helps you test the manifolds,
http://forums.iboats.com/mercruiser...haust-manifolds-leaks-288629.html#post1993095
 
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xadiohead

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

Fun Times said:
That might not be the best test to try!!!

If the water came up to the top of the (4) manifold holes, and you didn't seal the holes well enough from getting into the center hole and you blew air into the water jackets, I would have a hard time believing/trusting that you did not just blow water into the center of the manifold which will allow you to see water come out of the exhaust holes.

See if this helps you test the manifolds,
http://forums.iboats.com/mercruiser...haust-manifolds-leaks-288629.html#post1993095
Click to expand...

Haha yea I was laying in bed thinking about it and realized that was too easy. Went and looked at it again and realized my test made no sense. I was going to edit my post but you already busted my stupidity!

I will look at that other test tomorrow. Thanks
 
Fun Times

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

xadiohead said:
Can somebody please let me know if these are okay?
Click to expand...
For aftermarket, sierra is okay to use, but just know the better ones to consider using would be Osco Motors Manifold or Barr Marine. The part numbers look to be listed in the ebay link you just posted about half way down the page.

The most important thing to know is the green gaskets seen in the photos are not good to use at all as they have a tendency to leak. Be sure to buy and install Mercruisers OEM gaskets that go between manifold and risers with what ever you buy.

The price your paying for the services done is really not to bad. It can be a lot higher at a service shop.

Hope it all turns out well for you, good luck.:)
 
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Bondo

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

xadiohead said:
I had a new impeller installed before last season. I've been good about not running engine without water so I think I am going to wait a year on that. Well at least until I have all this stuff done and know my boat works.
Click to expand...

Ayuh,... The impeller pump, is Always the 1st place to look in Any overheat situation,....

Ya mighta picked up a piece of trash last year, blockin' the intake, burnin' up the impeller,....

It's reasonably cheap, 'n reasonably easy to change,....
'n Always the 1st place to look,...
 
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xadiohead

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Re: 4.3 merc Cracked block, blown head gasket, or manifods? (LONG)

I went ahead a pulled the trigger on everything: Sierra manifold/riser kit, OEM one to two piece manifold elbows, OEM manifold gaskets, Sierra circulating pump, OEM carb gasket kit and OEM thermostat. Total came to $850 (gulp!). Total with labor will be $1200. Probably too old of boat to be spending this kind of money but I just want to be ready for the summer. Hopefully all the parts will arrive for installation next Thursday. If I hear that hydrolock noise again, I will scream, and then probably cry! :faint2:

Wish me luck
 
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