1956 Evinrude Lark 30hp water flow issues

[wmbloke]

Hello!
This is the first motor I've attempted to restore and I would have been lost without these boards. They are an invaluable resource.

I have my motor pretty much up and running- carb clean, new points and coils, wiring and hoses, but I was running into an issue with water flow. Sometimes it pumped water fine, other times I'd get nothing.

I took off the lower unit. The impeller is in good shape. The wear plates look good and all of the ports seem free. I can blow air through them without issue. I reassembled and everything was working great, but later that night, the same issue, no water flow.

These 56s don't have a thermostat, do they?

Is there a way to test water flow without starting the engine? I feel last night I came dangerously close to cooking the engine before I noticed the water had stopped pumping.

Many thanks for any insight.

 

[racerone]

Please explain how you are testing this.-----On a boat floating in the water ?----In a wee bucket ?-----When testing in a bucket the water MUST be 6 / 8" above the pump !

 

[F_R]

Or worse yet, on some kind of makeshift hose attachment?

 

[wmbloke]

Testing in a 30 gallon can. I skim off the oil and top off most days. I'd say it's 6 inches or more above the intake. I'll see what the exact depth is when I get home. But until recently it's been pumping water just fine.

 

[wmbloke]

Today, of course, it's pumping water perfectly... I'm wondering if it's because I put the cowl on thinking I was done.

 

[oldboat1]

6 to 8 inches above the pump, not the intake. That's 6 to 8 inches above the lower unit joint -- point where the lower unit connects to the motor leg. Put the water about half way up the leg, and operate at idle or high idle only.

 

[wmbloke]

There is definitely plenty of water, but I'm still having the same problem. The motor was running just fine, pumping plenty of water, the next day, no water at all.

I took off the lower unit.
Replaced the impeller just in case
Wear plates looks good, nice and flat no pockmarks
Pin is good
Blew air through the intake, that seemed fine,
Blew air through the exhaust, that checked out as well
Reassembled
Started it up, nothing.

There's no gasket on the wear plate for this model, or for the impeller housing. Could I be getting an inconsistent seal?

It's driving me nuts! It either pumps water like a beast or not all.

 

[oldboat1]

Pull the l.u. again and make sure the water tube is in the water pump housing/grommet correctly. While the unit is off, manually run water up the water tube and make sure the water exits properly out the leg -- flushes system, Can use the garden hose and step down the nozzle to fit the tube (male end of a hose quick release can work).

 

[wmbloke]

Okay. That all checked out. Water flows throw and out the leg and the connection was fine. The lower unit is also full of water when I take it off. I'm wondering if the grommet is not creating a good enough seal. Is it okay to use some non-hardening sealer there? Seems like it has to be a vacuum issue... just not sure where.

 

[Roberthill]

Have a 1957 35hp ,when I flush it in a barrel water sometimes won't pump so I rev it up a little and it starts pumping , I think with all the exhaust it gets air in the pump. It always pump when the boat is in the water .

 

[oldboat1]

Okay. That all checked out. Water flows throw and out the leg and the connection was fine. The lower unit is also full of water when I take it off. I'm wondering if the grommet is not creating a good enough seal. Is it okay to use some non-hardening sealer there? Seems like it has to be a vacuum issue... just not sure where.

The lower unit will normally be full of water until it drains. The gearcase will/should not be. (It's sealed off.)

 

[wmbloke]

Have a 1957 35hp ,when I flush it in a barrel water sometimes won't pump so I rev it up a little and it starts pumping , I think with all the exhaust it gets air in the pump. It always pump when the boat is in the water .

Yeah, what I can't figure out is why it pumped so well until recently... Maybe I should put it on the boat and see what happens in a lake.

 

[racerone]

See post #2

 

[wmbloke]

I did see that. And despite the fact that the water level was fine while we got this thing running I raised the 30-gallon can up and topped it off... What do you know! Thanks a bunch.