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

From: drusilas@...
Date: Fri, 29 Aug 2008 05:02:51 -0400

Sorry, I thought you replaced the curved blade pump with the straight blade pump but I guess it was the other way around. The straight blade pump is the original one and the curved blade pump is the auto pump. Marine pumps use shafts and seals that will stand up to fresh water. These are the parts that will eventually corrode in an auto pump. In a car, the antifreeze prevents corrosion.

-----Original Message-----
From: JEFF DOOD <jdood@...>
To: Evinrude & Johnson Boats of the 1960's and 70's <omc-boats@...>
Sent: Fri, 29 Aug 2008 12:10 am
Subject: Re: [OMC-Boats] overheating - the saga continues

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 pro
blem "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 fact
ory 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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> >
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