Re: [OMC-Boats] overheating - the saga continues

From: JEFF DOOD <jdood@...>
Date: Wed, 27 Aug 2008 22:45:10 -0700

well.....that might be next..... but i hope not.

here's today's adventure for those who care. swapped out one water
pump for another - overheating problem "seems" to be WAY better.
atleast with heat sensing gun. gauge reads hot, but gun shows
otherwise. and while gauge shows 200+, manifolds only feel warm at
best. so gauge is off. all this testing was done while outdrive
was off, disassembled in garage. testing with hose and no
outdrive after putting on different water pump seemed to show temp
staying where it should. but again, just on hose. So outdrive got
assembled, put back on, and down to the river me and mechanic
assistant went to see what heat gun would show while underway. only
to find that the temp needle immediately moved up to 200+ within
seconds at idle. clear tubing showed no water really being
pumped. so apparantly, something wasn't put back together properly
with the outdrive. what a waste of time. mechanic asst did that
part. tomorrow it gets disassembled carefully to hopefully
visually see whats wrong. but he doesn't have a tank to fit
stringers, so after reassembly, it's back down to the river for a
test. and if no difference, back to shop. and so on.
testing that outdrive is going to be a complete pain. can't hook up
hose. no tank. this is wearing me out and costing a lot of
time. yet i'm encouraged with the diffence the engine water pump
made. again, feels so close to being solved.

  And the previous one? who knows where it came from or if it's
even OMC. might be automotive. (see pix). But here's the weird
part: my mechanic has some microfiche of early 60's OMC motors. the
one that we put on seems to definitely be the one that's supposed to
be on there. The givaway was that it has the main nipple for the big
hose, but then also has a smaller 3/4" nipple for something else.
This is fed by a bypass hole of some sort in the WP housing. Yet in
the diagrams it shows this extra nipple capped off! So that's what
we did. capped it off. so now it does nothing, just like it's
supposed to. So why is it there? what was it for - some factory
option or something? Air conditioning? Fresh water for a live
bait well? (kidding). here are the photos of before and after
water pumps. the bad one that was on there is the one with the
straight impeller blades. anyone have the first one? is it OMC?


On Aug 27, 2008, at 9:31 AM, Ethan Brodsky wrote:

> On Wed, 27 Aug 2008, JEFF DOOD wrote:
>> so he is completely baffled, i am too, and the only thing it seems
>> left to try is the water pump on the engine. taking my reserve pump
>> from my other engine out there today and giving that a try. if it's
>> heating up under throttle, it seems that maybe it's not getting the
>> water pumped around in the engine as it should be. but we've been
>> wrong most of the time so far. i asked about blockage in the
>> engine,
>> but they said the channels are so big it's not likely. so maybe the
>> pump thats on there is just not doing it's job as it should.
>> although it's such a simple device, i don't see how it couldn't.
>> any
>> other ideas?
> It'd be pretty stupid if this were the problem, but have you checked
> the
> belt? My belt loosened up one time and it would turn the pump fast
> enough
> at idle, but slip at higher RPM and the engine would overheat. It
> looked
> fine, wouldn't slip when moved by hand, and was turning at high RPM,
> but
> just not fast enough. I actually noticed this problem because my
> charging
> system wasn't working well, but then realized the engine was
> overheating
> too.
> The belt is adjusted by moving the alternator - I don't know what the
> tension spec is, but I got it really tight by tightening the bolt
> while
> pulling the alternator away with a prybar (i.e. stick). I think the
> belt
> deflects maybe 1/2" under 20 pounds of force or so.
> Ethan
> --
> Ethan Brodsky
> _______________________________________________
> OMC-Boats mailing list
> OMC-Boats@...

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Received on Thursday, 28 August 2008

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