diagnosis help / water pump impeller?

[nateo]

1986 alpha one drive / mercruiser 230.

Was cruising along at about half throttle everything perfectly fine. Then all of the sudden the engine sound/pitch changed, it didn't sound right. I immediately slowed down and the engine stalled. I opened the engine cover and a plume of smoke exited engine bay. It would start back up but was sounding rather terrible and would stall every time I put it in gear.

I brought it home and put it on muffs. It started up real easy but didn't sound normal. I noticed that there was not water exiting the bell housing like there normally is. Before I take this thing apart. Is this is a tell tail sign of water pump impeller going bad? This is my first thought but don't know why it go burn up while cruising in the water. Preceding this the only thing abnormal is that we were in some shallow sandy water before hand. Not sure if that might have plugged something up. But it ran fine for about 15 minutes after that.

 

[stonyloam]

Is this is a tell tail sign of water pump impeller going bad? .

It sure is. Count on replacing the entire pump housing and impeller. You may have also burned out your exhaust shutters too, look for what is left of them when you remove the outdrive, they would be in the exhaust cavity.

 

[achris]

If you've had no water running through the system for that long, ouch! What Terry said, plus the water pocket cover. You might want to do a compression test too. If the engine got really hot (what did the temp gauge show?) then the rings may have lost their temper and not be sealing properly.

Chris......

 

[thumpar]

The smoke would be your rubber parts in the exhaust burning up. I have been changing my impeller every 2 years now. We only get about 15-20 a year though.

 

[nateo]

ok, so I did a closer inspection today. Looks as though the big rubber boot (I believe its called a bellow) has split in two. This is weird because that was brand new this year. Wonder how that could have happened? Any ideas?

 

[thumpar]

Which "boot" are you referring to? Do you have a picture?

 

[nateo]

Well I got impeller off but it looks ok. Must be the bellow.

 

[ktbarrentine]

Doesnt make much sense at all... A failed bellows (if you are referring to a bellows, and not an exhaust boot) would not give those symptoms. Also, an impeller can "look" ok, but can be bad, as the rubber takes a "set" that makes it not flexible enough to provide enough flow. You need to get a manual (can get on on here) and do some research and it will help with the repairs (it will also help you with the "right" names for the parts). Pictures help us, also. Good luck!

 

[nateo]

The larger bellow on the top seems ok but the medium sized one underneth of it is the one torn. Is that the exhaust bellow? If so would that cause this issue?

 

[ktbarrentine]

The larger bellow on the top seems ok but the medium sized one underneth of it is the one torn. Is that the exhaust bellow? If so would that cause this issue?

Torn exhaust bellows will not cause your symptoms. Dig deeper. (some guys have even removed the bellows and replaced it with an exhaust tube). By the way,, notice that it is a "bellows" (yes, even just one.... like a fireplace bellows...a "bellow" is the sound we make when we find out we have to change one!):Cry:

 

[nateo]

What else would cause it not to pickup water (other then bad impleller)

 

[Fishermark]

What else would cause it not to pickup water (other then bad impleller)

Since your engine "changed pitch" and then would stall out whenever you would put it into gear... are you sure your outdrive is not locked up or otherwise trashed? Are you able to manually shift it into forward, neutral and reverse with the engine off and someone spinning the prop to lock it into gear?

Otherwise it could be as simple as a bag or something similar temporarily blocking the water inlet.

But the stalling suggests to me that you have further damage somewhere.