Still over heating

[kcfromohio]

92 4.3 liter Alpha 1 regular cooling system...
First I replaced the thermostat. no help
Impeller was replaced over winter, but I pulled the intake hose off the water pump to see if I had flow from the lower unit. I had the ear muffs with water turned to medium. There was some water flow. I thought it was ample.
I replaced the engine water pump, still overheating.
I ran it with the thermostat out. no help.
Maybe it's not enough water coming from the impeller. Is there way to check?
I'm wondering if I may have a blockage in the block or the intake manifold?
Any suggestions???

 

[Bt Doctur]

If you had flow with the engine off, you have an impeller issue. what is the temp on the muffs? remove the drive and insert a hose into the water inlet and compare readings.

 

[NHGuy]

http://forums.iboats.com/filedata/fe...2&d=1345224209
This links a to a troubleshooter for cooling water output. Basically, you test it in the water and for your ratio at exactly 1000 rpm for 15 seconds you should get 3.6 quarts of water.

If it's not enough water, you can test a few things.
Do you trust that the impeller was installed correctly?
Put on a section of clear hose, if the water is full of bubbles there's a leak in the pump area.
If it just doesn't give enough water and it's bubble free look for an obstruction. I'd have you remove the hose from the both ends of the power steering cooler under the port exhaust manifold. Blow some air or water backwards through the cooler or look through it for bits of impeller and other junk. Also, with the drive removed blow backwards through the hose from the transom and watch for stuff at the bell housing.
If the hose between the bellhousing and the transom is kinked it can restrict water too. I hope it's not that, they are a pain to reach.

 

[kcfromohio]

Bt Doctur, I started it and watched the water run out of the hose. it was a little more than a trickle.
As for removing the drive, I wouldn't think that's necessary. I can remove the gear case housing
and check the impeller and flush out the line from the top down. I think that's my next step.

 

[Eric 3.7LX Alpha 1]

There have been some on here with impeller pieces blocked in the water pocket cover. Which is what the copper pipe connects to on the bottom of the upper half of the drive. The impeller test he linked above will get you started.

 

[kcfromohio]

thanks NH Guy and Eric
on that now.

 

[kcfromohio]

No Title

Well there's my problem... Water inlet tube and impeller housing are melted.

 

[Bondo]

Ayuh,.... Looks like pretty much Zer0 water flow was goin' on,.....

The rubber parts in yer exhaust are now suspect too,....

Pull the cover off, 'n check the impeller,.... make sure ya find All the pieces,....

 

[poconojoe]

Check your exhaust shutters, they could have toasted too.

 

[kcfromohio]

The impeller was intact. However I had one heck of a time getting it off the shaft.

 

[Scott Danforth]

the impeller may be intact, however something prevented your flow in the first place that caused a no flow situation. that in turn caused the impeller to create heat since it wasnt being lubricated, and it melted your waterpump.

replace the pump in its entirety, backflush the lines from the thermostat housing to the raw water pump. This is also back flushing the power steering cooler (same as post #3). then backflush the lines from the manifolds to the thermostat housing.

since you had an overheat situation, your exhaust shutters are toast, and the two rubber exhaust hoses most likely are damaged as well.

 

[Eric 3.7LX Alpha 1]

Get yourself a complete kit including the upper housing for the impeller, not just the impeller.

If you have an Alpha One Gen 2 drive..... your OEM Quicksilver # is 817275K05

 

[kcfromohio]

I replaced complete sea water pick up pump. Impeller, housing, base and all the O rings and gaskets.
When I took the base out I noticed the shaft wiggled a little. Like the tapered bearing was moving around
in the race. is that normal, or should I check the bearing?

 

[kcfromohio]

Next step is to fix melted water tube issue.
I was checking past forums and found that an exhaust
shutter could be the problem. Some info I found says they should
be replaced every two years.

 

[Bondo]

I replaced complete sea water pick up pump. Impeller, housing, base and all the O rings and gaskets.
When I took the base out I noticed the shaft wiggled a little. Like the tapered bearing was moving around
in the race. is that normal, or should I check the bearing?

Naw,.... It all tighten's up as the rest of the pieces are installed,....

 

[kcfromohio]

Scott Danforth. just saw your post. I have the bottom end out now. Pulling off the upper housing in the morning.

 

[dingdongs]

goosed manifolds may be restricting the flow of water out and the flappers may have fallen and blocked the horns too.all the rubber pipework up top will have to be investigated too.Did you have this problem prior to the first impellor change over the winter?

 

[kcfromohio]

Todays project.


https://youtu.be/HIYfkPae4pM

 

[kcfromohio]

As I was pumping gear oil into the bottom fill hole,
I noticed oil leaking from that little hole on the bottom starboard side
of the housing.
When I ran it with earmuffs, I noticed water coming out of it.
I know gear oil shouldn't be coming out of it. ( Ididn't run it yet. I noticed the water
before I took it apart)

 

[kcfromohio]

PS. The water shutters were pretty easy to replace.
And not that much debris had been worn away.