cracked manifolds ?

[Matt Baker]

a couple quick questions.

I have an older 21' webbcraft with a new merc 260 in it with about 60 total hours. Through my own stupidity I forgot to drain the manifolds during winterization and both show the obvious signs of a hairline crack on the outside edge of the manifolds.

During de-winterization I ran her on muffs for about 30 to 45 minutes and she ran perfectly. There is no water in the oil and upon inspection of the valve cover I found no evidence of water either. I ran her at idle and at 1500 rpm's, again everything seemed perfect. I have ordered new manifolds and should be receiving them after the holiday weekend. The question is can I take her out without the risk of damaging anything. I should also say that the engine is cooling as should be and the riser elbows never got too warm to touch. The engine temp held after the thermostat opened at about 140-145 degrees. all input is appreciated. I got the boat last year from an individual who borrowed the money to have the engine installed at a mercruiser authorized dealer and that was the price I paid for the boat....again I don't want to run into problems further than what I already have....thanks much!!!

 

[cooter2506]

Re: cracked manifolds ?

I wouldnt run it just because of the CHANCE of water getting in to the engine. Just my opinion.

 

[HT32BSX115]

Re: cracked manifolds ?

OK,

couple of quick questions....

Did you drain the block and NOT the manifolds? If you DID drain the block (it's a new engine?) did you absolutely insure that you had all the water out of the block? (I.E did you poke a wire in the drain holes to clear it of possible rust flakes/debris?)

If you have cracks on the outside of the manifolds, you should assume you have cracks on the inside too.
That could allow water to enter open exhaust valves when you shut it down. (do you feel lucky?.........WELL DO YA?)


If you didn't drain the block.....well, you may have much bigger problems.....this is the time of year that the cracked blocks come out to play.......

 

[Matt Baker]

Re: cracked manifolds ?

To Answer your question...

I poured antifreeze into the block after running the whole outdrive in a small tank of 50/50antifreeze mix. In years past with my other boat I always drained the manifolds at the petcock drains at the rear of the manifold with the hoses removed. as I recall I was in a rush (my fault!!) last year and forgot this last step. the engine shows no signs of any damage and purrs like the new engine it is. The manifolds are original. the hairline crack is about 4 inches long on the outside edge of each manifold. Like I said I have new manifolds coming, but wanted to idle out to a cove over the weekend and throw an anchor out and enjoy the water. I live on Grand Lake in northeast Oklahoma. I have no intention of running it any harder than I did on muffs until the manifolds are replaced. As I said before I ran it for about 45 minutes and still have no sign of water where it should not be....thanks much!!

 

[wca_tim]

Re: cracked manifolds ?

I bought my current boat for next to nothing because the previous owner kept blowing engines.. thought he had a head with a hairline crack, warpage, etc, etc, etc... he had a cracked exhaust manifold and trashed no less than THREE engines before giving up and selling it...

 

[dgopetactical]

Re: cracked manifolds ?

To Answer your question...

I poured antifreeze into the block after running the whole outdrive in a small tank of 50/50antifreeze mix. In years past with my other boat I always drained the manifolds at the petcock drains at the rear of the manifold with the hoses removed. as I recall I was in a rush (my fault!!) last year and forgot this last step. the engine shows no signs of any damage and purrs like the new engine it is. The manifolds are original. the hairline crack is about 4 inches long on the outside edge of each manifold. Like I said I have new manifolds coming, but wanted to idle out to a cove over the weekend and throw an anchor out and enjoy the water. I live on Grand Lake in northeast Oklahoma. I have no intention of running it any harder than I did on muffs until the manifolds are replaced. As I said before I ran it for about 45 minutes and still have no sign of water where it should not be....thanks much!!

Pull the manifolds and and you will see if water is getting into your engine. If no signs of water (interior crack) then you can breath easier. Im glad to see you ordered new manifolds.
When I first got my 5.7 years ago I had the same issue inheirited from the previous owner. I made sure there was no water getting into my enging and then I used jb weld to stop the exterior leak until I could find the $450.00 for replacements,It worked for me. I got replacements 2 weeks later. I am no way recomending jb weld for any repair, just stating it put me back in the water for 2 weekends.
If you have an interior crack in your manifolds I dont think you would get water in your oil, water could get into the combustion chambers and rust things up or worse and could make your boat a big flower pot until you possibly replace the engine.#1 priority is making sure you had no leakage into your combustion chambers pull the manifolds now.
Knowing what I know now I would have never ran my boat back then with that issue its not worth it. $450.00 V.S $3,500.00 prices may vary
Denny

 

[dgopetactical]

Re: cracked manifolds ?

I bought my current boat for next to nothing because the previous owner kept blowing engines.. thought he had a head with a hairline crack, warpage, etc, etc, etc... he had a cracked exhaust manifold and trashed no less than THREE engines before giving up and selling it...

He replaced 3 engines and used the old manifolds every time???????????WOW
Denny

 

[HT32BSX115]

Re: cracked manifolds ?

Like I said I have new manifolds coming, but wanted to idle out to a cove over the weekend and throw an anchor out and enjoy the water.

I wouldn't take the chance up here in Wa State and we have FAR less nice days/weekends than you do in the summer time...


Good luck!


Rick