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

From: JEFF DOOD <jdood@...>
Date: Thu, 28 Aug 2008 21:10:21 -0700

so i'm alittle confused - which one are you saying is the automotive
pump? the one with the straight blades, or the one with the curved
blades? i guess the one with the extra heater nipple, which is the
one with the curved blades. but - as far as corrosion goes, the
blades on the curved one are plastic, and the housing is aluminum. ?

either way, it definitely seems to pump more than the straight blade
one. not sure what i'll do with the straight blader. i have two.

On Aug 28, 2008, at 10:54 AM, drusilas@... wrote:

> Jeff,
> Your old pump is the auto version which is all that's available for
> that engine now. The 3/4" nipple is for a heater hose. I have two
> 155 hp engines and neither one had the pump with the extra nipple.
> One of the original pumps started to leak out the shaft seal so I
> sent it out to be rebuilt and bought an auto pump to use in the
> meantime.
> I believe that OMC discontinued pumps for this motor quite a while
> ago and as far as I know, no aftermarket mfg is making them. The
> only options available are to go with an auto pump, get the old OMC
> pump rebuilt w/ marine grade components or find an NOS OMC pump
> sitting on a shelf somewhere. The auto pump will work for a while
> but will fail eventually because the internal parts will corode in
> fresh water. However, replacing it is not that big a deal and they
> are certainly cheap enough to keep a spare around. I've had mine on
> for 3 seasons now and it's doing fine. No overhating problems. I
> never got around to putting the rebuilt OMC pump back on.
> Dave
> -----Original Message-----
> From: JEFF DOOD <jdood@...>
> To: Evinrude & Johnson Boats of the 1960's and 70's <omc-boats@...
> >
> Sent: Thu, 28 Aug 2008 1:45 am
> Subject: Re: [OMC-Boats] overheating - the saga continues
> 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?
> jeff
> 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
> >
> > --> <a href=""> Ethan Brodsky </
> a>
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Received on Friday, 29 August 2008

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