Re: [OMC-Boats] Some Thoughts on Justin's Cooling Issue

Thanks for the advice Lee. I'm fresh from coming in from the boat.
Still have 42 year old grease under my nails. I'm happy to say that I
found the problem. I want to thank everyone for their input.
Especially Ethan who's been shooting me nuggets of advice off list. So
a big public thanks to him. He was a big help. Ok, so in case anyone
else goes through this, I'll explain what I did and what found as
best I can in the hopes it may help others. Warning. This is going to
get long, and it might get confusing. It's hard to explain and I was
too focused to take pictures to illustrate.

Ok, to review, my issue was no water flow through the port side hose
from the intermediate to the manifold. Removing the hose allowed the
water to flow, so my problem was obviously past the intermediate. And
since the problem was the same on the garden hose or when running in a
tub, I was able to eliminate the impeller as the culprit and rule out
poor water pressure from my garden hose.

So my first thought, and Ethan's suggested place to look was the
manifold. Seemed obvious. Problem was, with both caps off the manifold
on the port side, I passed a straightened coat hanger through the
manifold water jackets easily. At this point the problem should have
been obvious, but my lack of knowing how the system worked prevented
me from seeing it. But that comes later.

So I buttoned it all up and tried again. Same problem. Ok, now I took
off the covers on each side of the tilt pivot to look for clogs or
extra grease. Nothing. At this point, Ethan sent me a suggestion.
Start pulling off lines and blowing through them to see where air
wasn't moving. On the port side, one hose was blocked. On the
starboard, both side allowed me to blow air freely. Ok, now we're
getting somewhere. I knew the problem wasn't in the manifolds or the
intermediate. I also know it wasn't in the thermostat housing. That
only leave one place, the elbow between the manifold and exhaust.

So I removed both so I could compare them to each other. Once I had
them off, I finally got a real good idea of how the cooling system
works, and started making progress. If you look at the elbows, they
have 3 water jackets. But the manifolds have two. The cavity in the
elbow that the water enters, meets a dead end at the manifold. So
there is a passage in there to route the water into the other water
jacket. I hope this is making sense. So, after looking at the other
elbow, I figured out where the passage was. Some tapping to loosen the
carbon and some poking with a straightened coat hanger and a little
bit of air from the compressor and it was opened up. Flowing freely.

I bolted everything back together and lo and behold, water flowing in
both clear tubes! I can't tell you the relief I felt. One minor
problem left. I have a leak where the elbow on the starboard side
meets the manifold. So tomorrow I have to make a new gasket, no
biggie. But it does raise one new question. I was able to find the
leak because it was on the outside. But what if it was leaking into
the manifold? Once I bolt it all together for good, is there a way
that I can be sure it's not leaking into the manifolds? Cause I could
see that causing big issues. Is checking the oil for water the only
way? Thoughts?

Thank you all for your help so far. You've all been a great help.

On Tue, Sep 1, 2009 at 8:20 PM, Lee Shuster<lks@...> wrote:
> After thinking about your cooling issue some more today I'd offer the
> following troubleshooting tips:
>
> Water flow has an analogy with electrical current flow. In USAF electronics
> troubleshooting, we were taught to always break the circuit or path in
> roughly half. Make a check, verify and move "up" or down the path.
> Seems like that same approach can logically be applied to troubleshoot
> cooling flow?
>
> It seems you have described a situation where your tell-tale (pisser) is
> barely dribbling, right? One pivot end-cap (Port) apparently shows signs of
> water, while the Starboard side end-cap is relatively dry.
>
> I wonder if you could partially restrict or block flow on the "good" side
> and see if the flow increases or blows through any obstruction on the weak
> side?
>
> You could pull of the top cover of the intermediate housing, where the hoses
> connect to the exhaust elbow and look to see if there are passage
> obstructions between there and back to the pivot point?
>
> As mentioned before there is the distinct possible of too much grease
> clogging up the trunion/pivot water passages, where the intermediate and
> vertical drives mate up.
>
> There could also be an obstruction within one side of the vertical drive
> (upper gearcase), but that seems unlikely. Another real possibility is the
> impeller pick up tube and pickup screen mesh, which may be partially
> clogged?
>
> Further down stream you can check both elbows for obstructs. Just remember
> both the elbow and the manifold(s) have three separate passages: 1) Water
> supply, 2) Water return, and 3) exhaust gas.
>
> Your problem seems to be on the supply side, before even getting to the
> starboard exhaust elbow. The motor seems to be happy with a reduced supply,
> but then it's not doing much but idling so far.
>
> Lee
>
>
>
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Received on Tuesday, 1 September 2009