MasterCraft 190 Troubles

[Out_The_Front]

Well, I bought a 93 Prostar 190 last fall from a member of this forum and just got it ready for the summer. Spent a lot of time/money installing a new Holley 4160, exhaust manifolds, and raw pump then took it out for a test drive this weekend with the engine cover off. To my dismay, I found that both heads started weeping water from cracks once the engine got above 1500 rpm or so. Then I noticed later today that there was a rusty linear feature on the block behind the engine mount terminating between two freeze plugs (probably another crack). When I bought the boat there were rust stains on either side of the heads/block but the cracks were not apparent because they were so small and I assumed it was probably water dripping from the manifolds because they were in rough shape. Wrong! Now that I've seen the water dripping from the heads, the leaks start exactly were the rust stains begin and correspond perfectly. After running it for about 15 minutes I brought it back in and immediately drained the oil. Luckily there were no signs of milkiness or water. Now that I’ve seen the water seeping out of the heads, the cracks are more apparent and it makes me sick every time I look at the boat. Based on the amount of rust, it must have been run for at least one summer after they cracked. I find it hard to believe that the previous owner didn’t know about the issue and if he had known, it was low of him to not own up to it. It was even endorsed by his ski partner who is rather active and well known member of the forum. However, perhaps they didn’t know and I should give them some benefit of the doubt.

 

Anyways, moving forward I assume that I probably need to plan on repowering much sooner than I would have hoped. However, I’m not prepared to do so this summer and don’t want it to be a complete waste. Should I just slap some JB weld over the cracks and hope they are just external? Then wait for imminent failure. It looks as though they have been leaking for a while.

 

Also, does anyone have any advice/experience with repowering? I assume that I might as well replace it with a remanufactured 351w since I already have a new carb, manifolds, and water pump for that setup.

 

Any feedback is greatly appreciated. Thanks!

 

[oldjeep]

For a reman motor, these guys are great to deal with and well respected

 

For the rest - no water test when you bought it? What you are describing sounds an awful lot like freeze damage

 

 

[DW]

Your comments suggest the heads are the major issue, perhaps you could find a couple of used ones to swap out and do the JB Weld on the block. I have seen JB Weld last for several years on a block crack. Not an ideal solution but perhaps enough of a band aid to get you through the summer ski season. Have you done a compression / leak down test to verify integrity for the combustion chamber?

[mwetskier]

buy another mans boat buy another mans problems. jb weld *over* the cracks won't do you much good. using a die grinder and a small burr grind a bit of a groove along the length of each crack with the crack being at the center of the bottom of the groove. this will give the jb weld some side walls to grab on to. i've known a few guys who successfully saved a cracked block this way.

[keithh2oskier]

My dad JB-welded hair line cracks on the head(s) of their 94 MC 205. I think it had around 1400 hours when it first developed. Held for about 200 hrs when he replaced with probably re manufactured heads and then sold the boat.

[Orlando76]

I was in similar situation as you this past year, new carb, new dizzy, but worse. Mechanic misdiagnosed the problem as bad heads when it was really the rings, which I suggested to him to begin with. I ended up buying an ATK motor through Summit Racing (2nd ATK I bought, I've bought 4 reman'a so far). So far I've been happy, about 15 hours since installed two months ago.

[DmaxJC_ski]

For the cost of a new long block these days whether it be GM performance or ford Motorsport you can hardly justify salvaging anything, if your manifolds and other accessories are good yet that might be your best bet. By the time you spend the money to fix and freshen up the existing engine you will have spent as much or prob more then a new replacement. Plus you would be getting some warranty on a new one.

[oldjeep]

@Orlando76 - summit racing sells motors with marine cams and brass core plugs?

[Jody_Seal]

over the years I have found that a large percentage of water skiers know nothing more then where the gas fill is!! truly clueless and are not mechanically schooled. Also the 93 through 97 years the Ford heads were prone to crack and weep water just above the head bolts. I still see them today, they run fine just weep water and make the side of the block unsightly. the boat is a 23 year old and there will be more then just the engine fail in your future. I have used ATK and summit also provides the same engine.

[lottawatta]

Jody is right, those ford heads are known to develop those cracks and weep some water. One could reasonably expect there to be some minor issues like this with a 23 year old motor. As long as there is no water in the oil, I wouldn't worry about it. There is no reason to believe the motor won't last 100's of more hours while weeping a little water. While I can understand your disappointment, I think you are making a big deal about nothing in the scheme of used boat buying. just my 2 cents.

 

[Orlando76]

@oldjeep yep, they have quite the marine selection.

[JAG]

Remove the heads and have them magnafluxed.

 

Many years ago I was ignorant about replacing the impeller on my Four Winns I/O and one spring, the first trip around the lake overheated the engine as the impeller shredded.

 

It was found after months of diagnosis that the heads on the Vortec 4.3L had microscopic cracks, letting water into cylinders 1,3 and eventually hydrolocking the engine.

 

What I would do is remove the heads and have them magnafluxed. Here in the Motor City, there's quite a few motor shops that can do that.

 

if you suspect that's the only issue, get a set of rebuilt heads and install. That might be all you have to worry about. Small Block Ford and Chevy's are pretty bulletproof as I'm sure you know.

 

Or as others have said, it might be time for a new long block.

[Out_The_Front]

Thanks for all the input. I compression tested the engine right after putting the oil back in. I let each cylinder go about 6 or 7 cycles where they seemed to max out. All were between 150 and 160 psi. The boat seems to run very well and I did test drive it/go for a couple of pulls behind it before buying.

 

This past weekend I ran the boat on the water with the doghouse off to make sure the fuel line and manifolds were holding okay. Once the engine was warmed up and we gave it some power, we started to see smoke billowing from around the exhaust manifolds. We weren’t sure if it was oil leaking from the valve covers or just the paint on the new exhaust manifolds smoldering from the heat (there’s no water jacket where they bolt to the heads. Anyways, it was only the paint but it drew our attention to the area while the boat was underway. That’s how we noticed the water weeping from the heads. Under further investigation, we saw that they only start to weep once you begin giving the boat power. At idle the leaking stops.

 

I talked with the previous owner today and he swears up and down that he was unaware of the cracks before selling it to me. At this point, I'll give him the benefit of the doubt. I’m sure most people don’t study their engine at speed and I doubt we would have noticed if it wasn't for the smoking exhaust manifolds. He also says that he’s never seen milkiness in the oil so maybe they’re only external.

 

Attached are a few pictures. The cracks in the head are just above the head bolts as @Jody_Seal and @lottawatta mentioned (There are a couple more than pictured). The crack on the block spans between two freeze plugs. It's partially hidden behind the engine mount and can only be seen looking back to front.

 

Click here for Picture 1

 

 

Click here for Picture 2

 

 

Click here for Picture 3

 

 

Click here for Picture 4

[Gar]

I would not worry about it period. Ski!

Worry about it when it quits.

[Beastmode]

@Out_The_Front - don't worry about small external weeping cracks. I have a boat repair business and had a 93 Bendella that had an external crack on one head, compression was good and used it for 400+ more hours with no issues. I have a 94 MC PS now that has a small weeping crack and same - no issues to compression or mixing with oil. Boat runs great. when I get ready to sell it I will install a rebuilt head just for resale, but as a mechanic I know its fine.