1968HP Evinrude does not want to pump water (new impeller)

[andreipou]

Hello,

I am moving this question from another thread.

1968 40 HP Evinrude (40853D).

Lower unit was completely re-built including new impeller.

When motor started for the first time it started pumping water from top exhaust hole for a few mins , but then water stopped and I had to turn off because overheating.

I took LU off , checked everything and it looked fine, put another new impeller, put new thermostat - still no water from exhaust and overheats.


I removed thermostat\valve assembly and its cover and started engine and NO water coming to thermostat at all.

What can it be?
Obstruction somewhere?
How to find?

Also, I was thinking about removing thermostat and LU again and putting garden hose or even pressure washer to thermostat holes and see if it can pump out anything.
What do you think?

Tnx.

 

[F_R]

The black plastic thermostat housing and the white relief valve below it must be in there. Otherwise, air can travel down the return pipe to the pump and it won't work.

Do you have the motor deep enough in the water? That is a common no-pumping reason.

 

[andreipou]

Interesting thought....

I did not think about it because intake hole on this motor is very low, right above the prop and this is long shaft one, so when I fill my garbage can with water, it is way above the pump. Also, it is the same can as when it worked, but it is definately worth checking.

I will get taller can and try this weekend....

Any other thoughts?

Tnx.

 

[andreipou]

Interesting thought....

I did not think about it because intake hole on this motor is very low, right above the prop and this is long shaft one, so when I fill my garbage can with water, it is way above the pump. Also, it is the same can as when it worked, but it is definately worth checking.

I will get taller can and try this weekend....

Any other thoughts?

Tnx.

 

[Lewis1111]

Make sure when the lower unit if off that the impeller housing is sliding into the water tube. Lots of times when they are re-installed the water tube doesn't hit the impeller hsng. Also when apart you can blow air up through the water tube and be sure they are no obstructions.

If you want to eliminate some elements as the issue you can hook as garden hose attachment to the water tube and start the engine and see if you get any water coming through the tell tale that way..... If you do there is a issue with the gearcase-If still nothing the problem is in the power head.

 

[Barnacle_Bill]

You can find the weight at nadaguides dot com

 

[andreipou]

I finally had time to work on it and it was : A CAN!!!
With tall can it colled fine - 138F and sprayed from exhaust.

I felt stupid, but I have exactly ther same motor from 1971 and never had problem with regualr can...

You live - you learn!

Anyway this motor does not give up easily :

I can not make it idle.

I have to hold throttle control (where remote cable connects) open with my hand to keep it running after start otherwise it stalls.

Ignition is new
Carb is re-built

I re-did points using "wire" method from iBoats forum. I think it is the best I can do without special equipment.
Compression is 120 on both cylinders.
Throttle was set by the book.

What can it be?

Funny thing: It was idling when it was overheating.

 

[andreipou]

It was running on one cylinder...
When I re-did the timing I managed not to tack coil ground wire properly and it got chewed...

After I fixed it it runs like a charm!
Starts with half turn and cools fine.

Tank test and all carb tuning passed.

Next weekend hope to put oit on the boat.

 

[andreipou]

No Title

Finally big boy is up and running after 10 years of laying disassembled in my basement (and who knows how many years it was layning before me)!!!

Pushes my 1959 restored Larsen great! And suprisingly low noise!

Also, instead of sprayng water out as my 1971 Big Ski it spits very fine mist almost like vapour.

It was 38F on the lake and I had 20 feet tail of white steam behind me like I was running steam boat.
First I panicked because it looked like white smoke first, but it was 100% vapour.

Thanks everybody who helped to make it happened.

 

[Bosunsmate]

looks good,
nice hubcaps too, never seen anything like those

 

[andreipou]

This is original trailer for this boat , so I guess they are 1959 too.

 

[nwcove]

hard to tell from the first pic, but from the second pic......it sure looks like you need to get that motor up a few or five inches higher. nice looking rig tho!!

 

[andreipou]

It is long shaft motor on short transom, but it is fine.

I use this boat only for fishing and do not run it at full speed normally.
I just need to tilt it in a little and maybe add the fin I have somewhere in my garage.

 

[Sirrobin53]

I ALWAYS enjoy a POSTED happy ending :friendly_wink: I have a 57 larson crestliner as well. 14 foot open fishing and my motor is my avitar. Hope to take to NW Ontario next spring.

 

[Robert Ellis]

nice going - worth the effort n'est pas?! Those long shafts on a short transom sure do kick up the water lol

 

[racerone]

Go fishing below the dam at Ear Falls.