evinrude 40hp lark 1968 water pump trouble

[R.Johnson]

Re: evinrude 40hp lark 1968 water pump trouble

Evinrude Boater: There was a OMC service bulletin on this in the early years of these type engine's. The cracks' can cause the condition you discribe. Did,nt we discuss your engine in an earlier post, with some idea's on how to fix it?

 

[K.B]

Re: evinrude 40hp lark 1968 water pump trouble

Just now read the post. I have a 71 40 hp ev. that I had trouble w/a couple of yrs. ago when it was new to me. May not have a bearing on yours but sounds familiar to me. My head gasket was blown and would NOT pump water. Wrench told me to check the compression and see if the gasket was the problem and sure 'nuff. Replaced and been @ 110 on both cyls. ever since.

Just for the fun of it all, check.

 

[K.B]

Re: evinrude 40hp lark 1968 water pump trouble

Oh yeah, mine has no thermostat so I know nothing about that kind of problem. "Flathead" so to speak!

 

[R.Johnson]

Re: evinrude 40hp lark 1968 water pump trouble

K.B That certainly is not out of the question, it certainly seem's to be a puzzle.

 

[Evinrude Boater]

Re: evinrude 40hp lark 1968 water pump trouble

Evinrude Boater: There was a OMC service bulletin on this in the early years of these type engine's. The cracks' can cause the condition you discribe. Did,nt we discuss your engine in an earlier post, with some idea's on how to fix it?

You're right R.Johnson, mine has a few cracks and I think I will JB Weld them.

 

[redsmufc]

Re: evinrude 40hp lark 1968 water pump trouble

i have put the pump back together today there was a crack in the thin wall near the selecta rod i have jb welded it, sealed the impellor plate down.

do i need to use sealant between the pump housing and the plate?

fingers crossed going to test it tommorow. all going well

 

[samo_ott]

Re: evinrude 40hp lark 1968 water pump trouble

Is the impeller key there? It was mentioned but there was no confirmation?

I'd test the LU in a bucket, that will isolate the problem.

 

[redsmufc]

Re: evinrude 40hp lark 1968 water pump trouble

yes the impellor key is in place. is there a easier way of testing the lower unit without using a 3/4" chuck drill??

 

[samo_ott]

Re: evinrude 40hp lark 1968 water pump trouble

My LU's are smaller (18hp and down) and a 1/2" drill fits em all. Not sure how to turn yours at 5/8".

 

[Evinrude Boater]

Re: evinrude 40hp lark 1968 water pump trouble

If you have a small belt you can likely loop it around the driveshaft and put a rod in your drill to do the same. A pulley on the end of your drill would be even better.

 

[redsmufc]

Re: evinrude 40hp lark 1968 water pump trouble

many thanks for your help i'll give it a go

 

[K.B]

Re: evinrude 40hp lark 1968 water pump trouble

Ever check the compression yet? Don't rule the gasket out!!

 

[redsmufc]

Re: evinrude 40hp lark 1968 water pump trouble

Tested in drum today pumped water for a while then stopped it did throw a lot of water out of the drum the level dropped about 2" would that cause it.

 

[HighTrim]

Re: evinrude 40hp lark 1968 water pump trouble

It will pump until the water pump is no longer fully submerged.

 

[redsmufc]

Re: evinrude 40hp lark 1968 water pump trouble

hello thanks for your reply, water pump is still submerged must be a problem again!!! thanks again

 

[tashasdaddy]

Re: evinrude 40hp lark 1968 water pump trouble

the leg has to be submerged 1/2way up. the pump is not self priming.