Impeller not pumping water

[iggyw1]

I have been on here lately with differant problems, and first of all thanks to all that has replied. A new problem now. Motor is 1962 40 h.p. evinrude, electric shift model # 35933. I replaced the elctro magnets in the lower unit and everything there is now fine with the gears. Last week's test run, I had very good water flow with a new impeller AND new impeller housing, but I got water in the gear case. Re-did that now with new o-ring there and I put everything together, and I cannot get water to pump through the impeller any longer.

New impeller and housing, new grommets, tubes are good and facing correct way. Impeller started pumping a little bit. Took it back apart and found four impeller venes facing wrong way. I know I put them in right, how can they flip and face the wrong way?? I put the impeller back in, it started pumping again and quit. I took it apart and vanes are facing wrong way. Checked out ompeller against a differant new one at the marine parts dealer and the impeller and housing are the right ones. Now I put it back together and it will not pump at all. The water passages are clear, the impeller is new, the housing is new, what could the problem be??? Thanks again all!

 

[nwcove]

Re: Impeller not pumping water

if the impeller vanes are flipping opposite to the way you are installing the impeller, you must be installing it in the wrong orientation.....the vanes trail the shaft rotation. id check to make sure the impeller key hasnt fallen out or is slipping in the impeller.

 

[HighTrim]

Re: Impeller not pumping water

That is actually quite common, on all motors.

Reason being, as the motor slows to a stop, it tries to go through one more compression stroke, cant quite get through the whole stroke, then rolls backwards.

If you slowly pull it through a full revolution after it stops, and hold it momentarily until the compression leaks down it will keep the vanes orientated correctly and will add life to your impeller.

Regarding your issue. Drop the gearcase, flush the cooling circuit with compressed air to ensure it is clear.

If clear, ensure the water intake area is not clogged with debris.

If clear, open the impeller housing and ensure the pin is still as it should be in the slot of the impeller.

When reinstalling, grease the water lines and grommets and be careful that they do not pinch or jam, blocking flow.

 

[iggyw1]

Re: Impeller not pumping water

OK. Sounds like I'm doing everything right, but I'll try again and again 'til I get it. I will flush the circulating lines out to make sure they are not blocked, But I had a wonderful water flow prior to me taking the motor apart again due to water in the gear case. Thanks.

 

[iggyw1]

Re: Impeller not pumping water

Took the lower unit off again and tested everything for the impeller and cooling water system. New impeller, new seals, new ompeller housing, clear passages, no blocked tubes, tubes inserted right, no blocked pick up screens, no blocked nothing, yet I started to get somewhat of a water flow today but I would guess it is about 1/3 of what it should be.. Enough to barely cool the motor enough to run it for a while and that's it. Last week I had a very good flow after I put things together, but then I ran into water in my gear box so I took it apart to repair that and now the impeller won't pump. Think I should try another new impeller even though the one I have is brand new???

 

[nwcove]

Re: Impeller not pumping water

can you do a compression test? there is a chance the head gasket is leaking pressure into the water jacket.

 

[JDusza]

Re: Impeller not pumping water

I wouldn't go after any parts until you have done more.
You may have junk in the upper part of the system that has lodged in a new spot. I just did a repair on an engine with a brand new (water pump impeller) that wasn't pumping. Problem was the former repair guy didn't take out all the chunks of the old impeller and they jammed in the pump cover; like he never turned the cover over to look inside. The new impeller worked great but the waterway was blocked exiting the pump.
Did you change the lower water tube grommet and get the water tube in without folding the grommet over?
If you're sure the lower end is clear, then the blockage must be up top. Old pump petals or chipped grommet pieces may have moved up.
J

 

[iggyw1]

Re: Impeller not pumping water

Performed a compression test, got readings of 138 & 134 on a dry test. Just had a few thoughts though. I have no seal between the two halves (upper & lower half) of the impeller housing, and I was thinkig of trying some permatex or some other type of gasket sealer or gasket material between the two halves?? I did not have it ther before when things were working, but maybe there is a leak in between the two halves? It wouldn't hurt to put the gasket sealer between the two halves as long as I don't get any in the impeller area, would it?

Another thought (question) that I had: In putting the water tubes up into the grommets in the motor, could they possibly be going up too far and blocking off at the top of them? I am placing them all the way up until they stop when I have been putting them in. Maybe I should not push them up so far into the grommets up there??