1965 6 hp Evinrude erratic spark

[AlTn]

good deal on the electrics!...concerning the square pumps?, I see that they are the replacement f/p for the one you have currently, so yeah, they'll work...checked the compression yet?

 

[Bullie]

Funny you should ask that. I check spark and compression first when I pick up a motor. This one was 68/65 if I remember correctly. I later checked it with the drill and got high 80s on both. I checked it again while dealing with the electrical issues and it checked 87/60. I tried again and got matching high 80s. I figured I had just done something wrong. Flash forward to today. Even with good fire the motor wouldn't run right. Lots of white smoke and still wouldn't stay running if you shifted it into gear, it seemed to be heating up fast and would stop pumping water out of the holes in the leg so I decided to check the thermostat. No thermostat in it but it had a good bit of white crusty crud in there. Maybe salt? I pulled the head off to see if the water channels were clogged and they had lots of the white crud in them too and the gasket was blown in between the cylinders.

Any thoughts about water stopping flow out the leg? Water pump is new and pumping as it should.

 

[Bullie]

On the fuel pump, it was only leaking around the center screw so I made a new gasket and all seems well with it now. Pumping fuel well.

 

[ondarvr]

Water flow can become erratic out the holes in the mid section if the head gasket is blown. The combustion gasses leak out into the water jacket and overpower the impeller.

 

[Bullie]

Water flow can become erratic out the holes in the mid section if the head gasket is blown. The combustion gasses leak out into the water jacket and overpower the impeller.

Excellent info. Thanks. And, it makes perfect sense considering what I observed. When the engine first starts it pumps like it should and then tapers off. The higher the revs the less water I would see. Then if it was brought down to its slowest idle water flow would increase again. Thanks.

 

[Bullie]

Ok. New head gasket and compression is 88/89 and the motor starts much more easily and idles down much better and no more white smoke. So, we have whipped the spark issue and the idle/compression issue. But, it still isn't pumping water like I understand it should. I took a short video. http://vid230.photobucket.com/albums/ee260/Bulliedawg2/Outboard/20160219_185239_zpsvtsmbrtu.mp4
It will sometimes pump for several minutes before it stops. In this video I have the thermostat removed. But, it does pretty much the same thing with it or without the thermostat. I have run it with the thermostat cover off and it tapers off and stops in the same manner. Ideas?

 

[oldboat1]

might have to revisit water pump installation(?) Think I would first try flushing it down from the top, through the thermostat housing. Salt corrosion is a bugger -- another poster flushed with some vinegar, which might not be a bad idea. I think, though, that flushing might clear a blockage, or at least tell you if it's cleared out (water keeps flowing out the exhaust port, unlike current situation). If clear, think I would try running it again, then pull the l.u. again if flow stops -- suspect impeller issue of some kind at that point, maybe a problem with the pin/key?

Motor sounds good, anyway...

 

[Bullie]

I ran it with the thermostat cover off to see if water was pumping properly. Only for a few seconds of course as I don't want to overheat it. It will pump out the top and then taper off and stop just like it pumped out the leg. I have taken the pump off again and checked the installation. All looks good but maybe something is wrong with it.

 

[oldboat1]

thinking if you can push some flow down from the thermostat, you might clear it out (water is getting up from the leg, anyway -- seems like the pump is doing its job). If the l.u. is still off, can pump some water up the tube (t.stat cover on) and see if you can flush through. Also would be good to force some spray up the exhaust housing from underneath, maybe take a peek up there with a flashlight. (would back flush up the exhaust port in the leg too.)

One way or the other, might clear a blockage lurking in there.

 

[AlTn]

suggest you remove the lower unit and hook a garden hose directly to the water pipe going to the power head < may have to get some hose or tubing to slip over the water pipe then adapt the free end of that piece to the garden hose >...keep the water pressure fairly low and run the motor...can you see any interruption in flow out?..is the motor overheating?...will water flow out the thermostat housing?...if all now seems normal with the water flow through the power head...couple of questions on the w/p install...did you use any adhesive between the base of the w/p housing and the wear plate?...the underside of the wear plate and housing?...asking this because it's possible exhaust gasses could be entering the w/p housing causing some cavitation issues...you did remove as much scale as possible from the cylinder liners when you had the head off too?

 

[wrench 3]

The only thing that comes to mind for me is something loose in one of the water passages that washes up and blocks the water flow and then falls away when the engine is shut off. Was there any pieces missing off of the old impeller?

 

[Bullie]

I took the LU off again and flushed from the leg up and from the thermostat down. Water flows fine. I did scrape out as much of the scale as I could.

I did not run it with the water hose connected. I will try that tomorrow.

 

[Bullie]

The only thing that comes to mind for me is something loose in one of the water passages that washes up and blocks the water flow and then falls away when the engine is shut off. Was there any pieces missing off of the old impeller?

That makes sense but I haven't found anything yet. The water pump I took out of it looked good, nearly new.

 

[ondarvr]

I had a 9.9 that had erratic water flow, the culprit was corrosion under the water pump. At certain times it would stop flowing and get hot, after shutting it off you could restart it and it pumped fine. It was sucking air at times. I epoxied the area and leveled out, this sealed it back and it's worked fine for years now.

 

[HighTrim]

They work great as water pumps, not so great as air pumps!

Seal the plate down, and ensure the vent hole is open.

 

[Bullie]

I ran it this morning with the water hose connected to the pipe in the leg. Ran fan. No change in water flow.

I used sealer on the water pump last night and reinstalled this morning. It ran for a few minutes but the same thing happened, the water tapered off then stopped.

I am sure you guys are right and it is sucking air somehow. I had a pump do something similar one time and, even though it looked good and there was no sign of damage, a wear plate change solved the problem. I will order a new plate and see what happens.

High Trim, other than using gasket sealer like I did is there something else I should try? Where is the vent hole?

 

[AlTn]

does this motor have the "new style" pump housing < plastic housing with stainless steel cup liner>, or the "old style" all metal pump housing?...either way you should have an air bleed hole in the upper part of the housing < comes in from the side >...

 

[Bullie]

This one has the older all metal pump housing. I have looked it over twice and I don't see a vent hole.

 

[oldboat1]

couple of thoughts -- might resurface the housing under the plate, similar to what you would do with a cylinder head (wet/dry sandpaper on a hard surface) -- think that resembles the fix Ondarvr was describing on one of his motors. Might need the epoxy fill as well, like he describes, if the housing has some damage, maybe corrosion damage.

With the lower unit off, can immerse it in a bucket and test with a hand drill -- maybe replicate the problem. Just for grins, wouldn't hurt to be sure there is no partial intake blockage below the impeller.

Seem to recall a thread that dealt with drilling a vent hole, but maybe inventing that (senior moment). Maybe an iBoats search or google -- maybe some models prone to air locks.

 

[AlTn]

hard to see a hole when there isn't one, huh?...I looked at some pics of the older housings and yeah, no hole...sorry to have mislead you on that...does your wear plate have a small hole in?....just thinking.....in your test barrel is the water level within 4 or 5 inches of the exhaust relief hole?...is the motor idling in gear when the water from the exhaust relief tapers off and quits?