4.3 Merc Hydrolock/ finding parts help

dbismyname

Seaman Apprentice
Joined
Feb 9, 2009
Messages
44
Engine Serial OF148532
Transom OF257215
Drive OF237659
1995 Bayliner 2050

BackgroundMotor was running fine, hydrolocked on muffs after I got distacted while hose was cranked. Cleared out cylinders she ran great. After a week on the trailer she was hydrolocked at the ramp. Blew out cylinders but 3 spark plugs were cracked in the ceramic. Makes me think one side of motor may be overheating probably related to the hydrolocking. I find through all my research it must be leaky mani/risers. The generous amounts of form-a-gasket all around the manis and risers makes me even more sure of this.

Questions1. Where are the best prices on manifolds and risers? Found a complete kit on Ebay for $600 shipped
2. What size risers should I be looking for 3" or 4"?
3. Should I go ahead and do impeller?
4. What else should I go ahead and knock out while doing the mani/riser swap?
5. Should I be replacing the exhaust all the way from risers back to transom?

Also, any links to any sites with the necessary parts would be awesome. I try searching on iboats but have a tough time navigating the boat parts section.
Thanks in advance
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: 4.3 Merc Hydrolock/ finding parts help

Engine Serial 0F148532
Transom 0F257215
Drive 0F237659

1995 Bayliner 2050

Love it... Thank you, thank you, thank you..... Everybody reading this, take note!!! THIS is how you should all be starting a new thread!!!!

dbismyname said:
BackgroundMotor was running fine, hydrolocked on muffs after I got distacted while hose was cranked. Cleared out cylinders she ran great. After a week on the trailer she was hydrolocked at the ramp. Blew out cylinders but 3 spark plugs were cracked in the ceramic. Makes me think one side of motor may be overheating probably related to the hydrolocking. I find through all my research it must be leaky mani/risers. The generous amounts of form-a-gasket all around the manis and risers makes me even more sure of this.

Questions1. Where are the best prices on manifolds and risers? Found a complete kit on Ebay for $600 shipped
2. What size risers should I be looking for 3" or 4"?
3. Should I go ahead and do impeller?
4. What else should I go ahead and knock out while doing the mani/riser swap?
5. Should I be replacing the exhaust all the way from risers back to transom?

Also, any links to any sites with the necessary parts would be awesome. I try searching on iboats but have a tough time navigating the boat parts section.
Thanks in advance

1. My personal preference is to use OEM (Mercruiser) manifolds and elbows. Unfortunately they are the most expensive. But manifolds/elbows are very much 'you get what you pays for' items. A couple of brands that seem ok are Barrs and Osco. Avoid like the plague Mallory, GLM and Sierra.. VERY thin castings, corrode out super quick.
2. Your serial number gave me that information ;) 4"...
3. I would.
4. Check you exhaust shutters. From your engine serial number you have the old style, you need to upgrade to the new ones. The part number of them is -807166A3. They come as a pair, for about $70. Also check the rubber boots that couple the elbows to the tube, and the tube to the exhaust Y-pipe....
5. No need.

I use Mercury Mercruiser engines and parts for quite a lot of parts. Also find a lot of what you're looking for on iBoats....

Chris........
 
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tpenfield

Moderator
Staff member
Joined
Jul 18, 2011
Messages
17,621
Re: 4.3 Merc Hydrolock/ finding parts help

Since you hydro-locked a couple of times and you busted some spark plugs in the process, I would run a compression test and even a cylinder leak test, just to see if you have any damage to the engine.
 

dbismyname

Seaman Apprentice
Joined
Feb 9, 2009
Messages
44
Re: 4.3 Merc Hydrolock/ finding parts help

Thanks so much for the info guys, a compression test is definitely on the list.

Achris, are the Sierra manifold kits THAT bad? I bought this boat for cash this year and plan to get a couple years of family use then sell it. Not to sound like a slimy used car salesman but saving $400 on manifolds now will put money in my pocket when selling. If its just a longevity issue I can't justify the cost for OEM on this boat.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,465
Re: 4.3 Merc Hydrolock/ finding parts help

Thanks so much for the info guys, a compression test is definitely on the list.

Achris, are the Sierra manifold kits THAT bad? I bought this boat for cash this year and plan to get a couple years of family use then sell it. Not to sound like a slimy used car salesman but saving $400 on manifolds now will put money in my pocket when selling. If its just a longevity issue I can't justify the cost for OEM on this boat.

Ayuh,... The Chinese manifolds need thorough inspections before ya run 'em,....

The 1s I bought awhile back, needed the riser/ manifold gasket surfaces machined Flat to hold a gasket,...
The inner circumference was .020/ .030" lower than the outer,...

Coulda lost my motor, tryin' to figure it out,....

I hear core-shiftin' in the castin' process also causes many other Problems,...
 
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