Motor died. Two mysteries. Is it the snap ring on the impeller?

[ernst]

Start the engine. While the engine is running shake the wiring between the key and coil +. If you have an electronic fuel pump shake the wiring between coil + and the fuel pump while the engine is running.
There may be a lose or intermittent disconnect in the wiring.
If you have an electronic fuel pump and there is wire that goes from the fuel pump to the starter let this wire loose at the starter and inspect it.
On my A4 the insulation was worn and the wire was shorting out back by the distributor where the wire turns towards the starter solenoid. Kept me guessing for many months.

TRUE GRIT

I did wiggle the ignition wires. No effect.

As for the low-voltage wiring, yes, I should follow that up.

Fuel pump is mechanical.

tx

[ernst]

Another couple hours work on the motor. I replaced the V-belt, installed it at 130# when new and tightened to 90# after 5 minutes of running, per instructions from the manufacturer (Gates). Was able to use my Krikit gauge rather than using the 'rule of thumb' and I think the belt was too loose previously. It still worked for a decade so I don't complain.

The more I think about it, the more I feel that one of the 'mysteries' may be solved: where the coolant went. My use of the diaper under the motor may have obscured the gradual loss of the coolant. At least this is my working hypothesis.

As for how it got lost, I am not quite sure yet. I re-tightened all hose clamps even though there was no hint of a loss there. I replaced the paper gasket of the coolant pump again (and discovered that I had inadvertently put two in but that would not have caused a leak, right?). Following John Cookson's advice in another thread, I put a thin layer of PTFE pipe dope on both sides of the new gasket. Did not see any leaks during the 5 minutes I ran it (for the final tensioning of the V-belt) but that may not mean much.

Question: Based on the coolant I collected under the motor, I think I am still about 2 qts shy of what should be in the system. Will it be sufficient to keep the overflow reservoir filled and let the motor 'burp' out the air? Or do I have to go through the process of disconnecting the various hoses etc and fill up the block as prescribed in the Indigo instructions for the first filling of the system?

Oh, btw, I found the snap ring from the impeller that I thought I had lost, in the bilge! But I suppose there is no reason to put it back on, right?

[ernst]

I went sailing this weekend and everything worked flawlessly. So I will conclude that the mystery shutdown was due to a cosmic ray and I hope that it will not re-appear. The good thing is that I learned a few things on the way so the effort was not wasted. Thanks again for your help!

[Dave Neptune]

Ernst, thanx so much for chiming in. I is always good to hear the efforts were well worth while.

Dave Neptune

[capnward]

Those darn cosmic rays will get you every time. Glad your engine is running well.
Sometimes, when I suspect a slow leak, I place some unbleached paper towel, natural color, under the area suspected. When it gets wet it becomes noticeably darker.
On my boat, there is a high point in the curve of the water hose between the bottom of the heat exchanger and the Fresh water pump. This curve is to keep the water hose off the engine, because I mounted the HX so that the bottom of it is about 2 inches away from the side of the manifold. If I drain the coolant to change the impeller, then reattach the hoses and fill the heat exchanger, air remains in the high point of the hose. This keeps the pump from working to bring water from the HX, and the engine will overheat. It is also hard on the impeller. I have learned to briefly remove the intake hose on the pump, to enable that air pocket in the hose to fill with water, then refill the HX.
The purpose of the snap ring on the impeller is to keep the shaft from moving back and forth, so the impeller and the seals last longer The newer Moyer flange pump, which has no grease cup, has no snap ring on the impeller. The packless bearings prevent the shaft from moving. I suspect when I rebuilt my pump four years ago, I did not tap the bearings in all the way to meet the stops on the shaft. As a result the shaft could "float", to use the Moyer Co. term, and the seals failed this year, leading to milky crankcase oil.
I still suspect you may have an intermittent coil that could shut down after some hours of running, and getting too hot. I have a Moyer coil with no external resistor. I have left the ignition on overnight with no apparent ill effects at the time, but much later had to replace the coil, which still worked, because the rim around the top was rusty and leaking. I had a bad overheating episode once which may have cooked it. I have never had the engine suddenly quit because of a failed coil, but I rarely run it for more than an hour at a time. I think I have replaced coils twice in 20 years.
Ernst, your efforts to keep learning about your engine will result in many years of trouble-free operation. Happy Sailing!

[ernst]

I may have to rethink the cosmic ray theory of mine. I went sailing this weekend and, just as I was about to enter the planned anchorage (in Worton Creek, for the Chesapeake cognoscenti), the temperature alarm came on! I anchored right where I was, in the approach to the Creek, and ended up staying there the whole night.

So what caused the problem? I am pretty sure now that the water pump is leaking from the weeping hole: when I feel there, it is definitely moist. Rather than blaming a cosmic ray, my new theory is that this caused a slow leak which was hidden by my habit of keeping a diaper under the motor.

I should probably be prepared for this to happen. I have NEVER been able to get the impeller off its axle without the axle coming out. I understand that this is not good for the seals, right?

I have an Oberdorfer pump and I understand there is a rebuild kit for $153.- (https://moyermarine.com/product/repa...mp-csob_09_70/). There is also the all-new-all-improved Moyer pump for about twice that much (https://moyermarine.com/product/mmi-...p-csob_00_365/). I am reasonably handy (I think) but I am not a mechanic and pressing bearings or seals on axles is not something I am familiar with at all. So I am tempted to go whole-hog and get the new pump (it is 100% compatible, right?).

Good decision? What say ye?

[Al Schober]

I used an Oberdorfer pump for years, continually dealing with seals & leakage. Never was able to get it 'right'. But being raw water cooled, it didn't really bother me - there was plenty more water where that came from.
Then I changed to glycol cooling, and the leakage from the Oberdorfer was suddenly critical - it was like losing blood! Changed to the Moyer pump - no regrets.

[JOHN COOKSON]

I used an Oberdorfer pump for years, continually dealing with seals & leakage. Never was able to get it 'right'. But being raw water cooled, it didn't really bother me - there was plenty more water where that came from.
.

This summarizes my history with the stock Oberdorfer H2O pump also.
When I finally threw in the towel and went with the Moyer pump my cruise running temperature dropped 40 degrees - from 160 to 120. Nothing else was changed. No acid flush either.
The Moyer pump is just plain a better pump.

TRUE GRIT

[ernst]

This summarizes my history with the stock Oberdorfer H2O pump also.
When I finally threw in the towel and went with the Moyer pump my cruise running temperature dropped 40 degrees - from 160 to 120. Nothing else was changed. No acid flush either.
The Moyer pump is just plain a better pump.

TRUE GRIT

Thanks, Al and John! The order will go out to Moyer today or tomorrow.

[capnward]

When you buy the new Moyer pump, get the rebuild kit too. It has directions for replacing shaft, seals, and bearings. Not too hard to do with the right tools. You will still have to monitor the pump for leaking, and fix it when it does. The seals on my Moyer flange pump have failed twice in ten years. The first time it overheated the engine, putting coolant into the bilge. The second time the engine ran hotter but ok, and coolant water got by the oil seals into the crankcase.

[Dave Neptune]

Caution

Ernst, do not use any extra or thicker/thinner gaskets on these style pumps. The width of the impeller plus the gasket is what the clearance is set for. If you go to a thicker one the pump will loose pressure as the impeller vanes will allow water to leak past. And to thin will pinch and destroy the impeller.

Dave Neptune

[Sam]

I'[[ chime in a little here. Here in Chicago we have short Lake Michigan season - about 5 months. On my early model A4 I upgraded from a little "Sherwood" pump to the Ober about 25 years ago. With the old style Dole tstat the beast runs a steady 140 F raw water. I pull the shaft out/impellar out every season for winter layup carefully using small needle nose pliers and lubricate it. I did slightly bevel the shaft end to minimize seal damage on extraction /install. every other outing I give the grease cup a half turn After examining the impeller I usually change every 2 -3 seasons no matter [snap ring is important] and change the moyer gasket almost every year. Cooling/pump has been problem free so far with this routine.

[ernst]

When you buy the new Moyer pump, get the rebuild kit too. It has directions for replacing shaft, seals, and bearings. Not too hard to do with the right tools. You will still have to monitor the pump for leaking, and fix it when it does. The seals on my Moyer flange pump have failed twice in ten years. The first time it overheated the engine, putting coolant into the bilge. The second time the engine ran hotter but ok, and coolant water got by the oil seals into the crankcase.

Yes, I understand that I need to keep an eye on the pump, as on everything else. But I do hope that I won't need the rebuilding kit for a good while, with a spanking brand-new pump! I can only hope that my experience will be better than yours. Holy Moly, on the THIRD pump in 10 years!! For the record, my current (now leaking) Oberdorfer pump came with the boat in 2001, it had been in there for an unknown amount of time.

FWIW, I placed the order for the new (MMI) pump today. I did order a spare impeller but no rebuilding kit.

[ernst]

Ernst, do not use any extra or thicker/thinner gaskets on these style pumps. The width of the impeller plus the gasket is what the clearance is set for. If you go to a thicker one the pump will loose pressure as the impeller vanes will allow water to leak past. And to thin will pinch and destroy the impeller.

Dave Neptune

All I ever used were the paper gaskets that I ordered from Moyer. I did accidentally use two gaskets on one of the pumps (forgot whether it was the coolant or raw water pump) which did not have any noticeable effect. This has now been corrected.

I also put the plumbing goop on both of the gaskets that someone recommended (was it you?). This has cured the (very slow) trickle of water/coolant through the face plate.

[ernst]

I'[[ chime in a little here. Here in Chicago we have short Lake Michigan season - about 5 months. On my early model A4 I upgraded from a little "Sherwood" pump to the Ober about 25 years ago. With the old style Dole tstat the beast runs a steady 140 F raw water. I pull the shaft out/impellar out every season for winter layup carefully using small needle nose pliers and lubricate it. I did slightly bevel the shaft end to minimize seal damage on extraction /install. every other outing I give the grease cup a half turn After examining the impeller I usually change every 2 -3 seasons no matter [snap ring is important] and change the moyer gasket almost every year. Cooling/pump has been problem free so far with this routine.

(red added by me) I was under the impression that the snap ring is not important and can be disposed of. Somewhere I read that it is only installed for transport and has no functional role during operation.

Was that wrong? If yes, what effect would it have if the snap ring is omitted? As you may have seen earlier in this thread, I lost it and did not care about it because of what I just wrote. I accidentally later found it and this time I threw it away for the same reason.

Please tell me I did not do something stupid...