does this impeller housing say: I cracked your al intake?

[Bounce19712]

454 mercruiser 330, aluminium intake manifold.

a while back I called the mechanic when my boat was in the shop...they told me "yeah, we're running your boat right now in the tank (outdrive tub)... I said woah, I've got a seawater pickup! He said," it's allright it was only a couple minutes".... I took that to heart and brought my boat home.

when flushing it in my driveway prior to taking it out for the first time I heard some air noise on top of the motor...found a crack in the intake..took it back... I had to pay to get it replaced...apparently the assistant mechanic never told the owner about his running my boat without water..

I just de-winterized the boat this July and pulled the impeller because I thought it gave up the ghost on me. I believe now I didn't wait long enough for the water to run through the engine...but nonetheless...it helped me find my impeller housing burned up when I went to replace impeller.

I took the impeller housing in to the mechanic and he asked if I ran it without water...I told him his assistant did it and he gave me a free impeller kit.

anyone have overheat experience with impeller housings? could this have cracked my intake manifold?

what should I look at next before taking my family out in the boat?

thanks

 

[Bounce19712]

more to the point does that impeller housing look like it could have overheated the motor?>

 

[alldodge]

Your housing looks pretty rough and should be smooth. Your impeller has a mark on every blade and this tells me there is something in the housing causing it. If it cannot be cleaned up it needs to be replaced.

My guess is the water pump could not pump sufficient water at speed. That said, unless the engine was majorly overheated I wouldn't think the intake would crack. Was there any time where the temp on the engine was seen?

 

[Bounce19712]

there was no water.....they ran the motor on trailer with no water. (it's a thru hull water pickup and they thought it was lower unit water pick up)

no engine temp was noted by the guy who ran it without water.... I just happened to call him when he was running it at the boat yard and he said "I've got your outdrive in the water tub to run the motor"

the housing plastic may have blistered and chunks of it damaged the blade where you see the nicks. I pried loose a few chunks of melted plastic while examining it.....I replaced with a new one.

your answer helps though...if you don't think that much heat/friction/damage to the inside of the impeller housing doesn't scream at you " check other parts of the motor; you've melted something" then I'll mark your response in the "don't worry too much" category.

thanks!

 

[alldodge]

OK understand what happened better. If your exhaust hoses/boots are not melted then you may be OK. Check them and see if they feel soft. If still firm I don't think it ran very long

 

[Bounce19712]

I will check asap! thanks !

I have to adjust one anyways because they did not seat it fully (the starboard riser boot)

 

[Bondo]

.found a crack in the intake..

Ayuh,.... The intake is a big chunk of aluminum,.... Where, Exactly, was it broken,..??

I agree, the raw water pump is Beat,....

 

[Bounce19712]

thanks for the input! I can't find the actual photo right now...but I made an example pic...see the red marked area. (the actual crack on the manifold was on starboard side closer to the transom

 

[Volphin]

Does the crack go all the way across the runner? Are you losing vacuum through it? Doubtful that a few min would crack it. More likely a casting defect.

 

[Bounce19712]

it was about an inch and a half crack...I only discovered it by hearing it suck air when running on the trailer.

Good input I appreciate it!