Cracked Block (looking for a quick fix)

[seafan2824]

Hi all,

recently inherited a 1988 citation with the 4.3 mercruiser. Picture attached of the cracked block above starter. Wondering if it’s fixable to patch or if I should just scrap the engine and move on to a different boat. Boat would cut out at 3500rpm under load. Boat has new plugs, wires, distributor, fuel filter, new carb, basically everything but a power steering pump. Just trying to see if this is something I can tackle at home.

 

[Scott Danforth]

Cracked block is result of improper winterization. Most likely the intake manifold and exhaust manifolds will have beed compromised. Your motor wpuld have come with batwing manifolds, they should be replaced

Get a 1988-1991 4.3 from an S-10 or silverado, strip it down to the long block. Install brass core plugs, marine head gaskets, then swsp over the marine accessories and buy a new intake and exhaust

 

[seafan2824]

Will upload picture of crack in the morning... will not let me upload from my phone to the forum...

 

[seafan2824]

Here is the picture of the cracked block., You are correct. About 10 years ago the boat was improperly winterized. I would guess that the reason the boat starts to cut out around the 3500 rpm mark would be because of this crack. Just wanted to know if it was fixable to use for a few summers. I don't see us keeping this boat if we need to stick a few thousand in it for a new motor + labor...

 

[Grub54891]

An external Crack shouldn't affect the way a motor runs. An internal one will. Is the oil milky? There are so many variables to a question like this, compression test to see where the motor is as far as wear or gasket/valve issues, fuel system checks, the list goes on. An external Crack is a good indication of underlying issue.

 

[Scott Danforth]

you most likely have either electrical or fuel related issues for the cut-out issue.

back to the crack, most 4.3's do not just crack externally. Boats cost money, about $3-500 a year on maintenance items alone. your looking at a $350 used motor, $100 gasket set, $10 core plug set and you have a new long block. for under $500

the intake I would recommend you buy off of ebay or craigslist to save a buck or two, and you will need new manifolds if you have the batwings anyway, so that is about $1000

 

[seafan2824]

Here are the videos I shot of it last summer... first link was from June when boat would cut out around 3500 RPM...

https://youtu.be/8_fZFP6sArk

After this issue, we had carb rebuilt, new distributor (Cap & rotor), new plugs and wires, new fuel filter, and new alternator... It ran 100 times better. But eventually the issues came back with cutting out one the boat planed out.


https://youtu.be/P-eB7xsQ0ag

I can only imagine how much fun it would be to chase an electrical issue down on the boat.... It's been in my fiance's family since new in 1988, so she's got some sentimental attachment to it... but the 25 years of crap maintenance probably did this boat in big time. We got the boat for free, but stuck about 1400$ in it last summer with parts and labor total. I'll be headed up to the cabin this weekend to get it running and back in the water to see if wants to work...

 

[Lou C]

Before you start sinking money into it check the structure for rot as much as you can. If it’s still solid and the drive/transom is ok then the engine job makes sense. Cheapest way to stay in boating esp if you are handy.
ps with the work done did anyone check/replace the anti siphon valve? This is a common problem if that valve restricts fuel flow.

 

[Grub54891]

Watching the videos, almost does look like a fuel issue.

 

[seafan2824]

I do not believe my guy did check the anti siphon valve... it's just really odd that once we did all the other maintenance items that boat ran really well for 2 or 3 weekends... then when the alternator died and I replaced that that the issue came back. Is there an easy enough way to test that anti siphon valve?

 

[seafan2824]

We also checked the fuel tank last season, no sediment of any kind in there. Clean as a whistle... The back floor is starting to get soft. The front 2/3 has marine boat re-carpeted over the old floor... "Yeah I know, not the way to do it...." but it wasn't my boat at that point... transom is solid. Boat has 228 hours and its 32 years old... so sat out of the water 95% of the time when not used.

 

[Lou C]

the problem with rot repair is that the more you look the more you find...I fixed a LOT of rot on my also 1988 boat, did the most of the deck and stringer repair back in 2005, then fixed a spot in front of the gas tank in 2010, now am fixing one vertical piece, under the deck on top of the stringers, just a piece of 1/2" ply that rotted prob due to water getting in via the ventilation openings and running down at the rear of the boat...

Carpet over a plywood deck is a rot generator, its not just the boat being in the water its rain water that gets in and moisture in the air that cannot evaporate because the carpet holds it all in. When redid my deck all the carpet went in the trash can and the deck that was repaired is still good nearly 15 years later.

 

[seafan2824]

The new floor was added on top of the old carpet and deck. The wood got coated with plexiglass or something along those lines, and then was carpeted. My wife's stepdad works for Cruisers Yachts... so has access to some good stuff. What would be the proper way to run the boat off an external fuel tank to go test it out. If all ran well on that test run then my best guess would be that the fuel pump is going..

 

[Scott Danforth]

The new floor was added on top of the old carpet and deck. The wood got coated with plexiglass or something along those lines, and then was carpeted...

That is called a "deck over" thqt is the equvalent of taking a ruaty car and using duct tape and bondo to cover rust holes the size of basket balls and rolling the odometer back, then selling it

This means that the old floor was rotten. Floors are the last thing to rot, the first being the transom and stringers

 

[seafan2824]

Update... boat looks like it had a new fuel pump put on last year.... now I’m even more concerned as the first guy we took the boat to didn’t know wtf he was doing with about anything... definitely not oem and pump is still shiny.. so boat is going in the water today and I’ll take some videos of what it does.

 

[Scott Danforth]

just hope that is a marine fuel pump and not an automotive fuel pump.....

 

[seafan2824]

How would I be able to tell if it was an automotive fuel pump vs marine? Rode it around the lake earlier today, same thing. Anything over 3200 rpm and it wanted to quit. High idles at 4K no problem when at the dock and not in forward..

 

[Grub54891]

A marine pump has a fitting on the pump where a hose hooks up, that hose runs up to the carb. If the fuel pump ruptures, the leaking fuel gets routed to the carb. Without that fitting and hose, If the fuel leaks into the bilge, and ignites, you get the big boom, and serious injuries to you and your passengers. Look at the pump and look to see if that hose is routed properly

 

[seafan2824]

It’s a marine fuel pump then, it’s got a small hose routed up to the back of the carb.... I think I’m going to start with the fuel lines from the tank to the fuel pump. It’s an original (32year old) hose... I’m about 95% sure the hose that’s on the boat is toasted. Hard to squeeze. Getting oil and filter this week and once I head back up north this following weekend I’ll work on that and pick up some fuel line. I believe it’s 5/16 inside diameter but not sure. Hopefully it’s a quick change for the fuel line from tank to fuel pump.

 

[Grub54891]

The fuel line itself from the tank should be marine rated also.