1969 Lark X 40hp Pee hole/Thermostat Water Pump

[gusthewonderslug]

Hi all
I took Smoking Joe out yesterday arvo and noted I lost power after about 10 mins of fast running,(started straight back up and ran fine) I then noted that I was getting a lot of steam coming from the Pee hole and not a lot of water.
After the loss of power I noted that at low to medium revs I get plenty of water coming out but at high revs not so much!
on coming ashore I checked the thermostat and it appears to open at 68 deg and everything appears to be clean and I have recently replaced the impeller.
Any Ideas on what would cause this.

 

[Daviet]

Re: 1969 Lark X 40hp Pee hole/Thermostat Water Pump

You have a tell-tale on that year of engine, did you install it yourself?
Just something think about.
Have you checked compression?
I have seen in the past that a defective head gasket can cause your problem. Sometimes a head gasket can leak compression into the cooling system at high speed and overcome the waterpump pressure and cause the engine to over heat.

 

[gusthewonderslug]

Re: 1969 Lark X 40hp Pee hole/Thermostat Water Pump

The tell tale is the exhaust port on the back of the leg
This is where I'm getting water out at low to medium speed but at high speed only a little water and lots of steam
Any ideas
And should I get water out at high speed

 

[Daviet]

Re: 1969 Lark X 40hp Pee hole/Thermostat Water Pump

The exhaust port should have water coming out of it at high speed, was it that way before it stalled?
When was the last time the water pump was serviced?

 

[gusthewonderslug]

Re: 1969 Lark X 40hp Pee hole/Thermostat Water Pump

The exhaust port should have water coming out of it at high speed, was it that way before it stalled?
When was the last time the water pump was serviced?

Daviet

The water pump was replaced a few weeks ago, I'm now thinking that the issue could be a dying coil as when I go to shut it down it doesn't kill the engine and it still wants to run on one cylinder.
Thinking about the issue I'm thinking that once the coils get hot one starts to break down, as soon as I throttle off and cruise for a while the missing plug fires back up again.
The other small issue I have is that the engine wants to backfire when idling , I'm pretty sure that this is the timing issue but I'm a bit confused as top mixture screw is turned out about 4 turns which would seem to be rich.

 

[gusthewonderslug]

Re: 1969 Lark X 40hp Pee hole/Thermostat Water Pump

see video attached

 

[gusthewonderslug]

Re: 1969 Lark X 40hp Pee hole/Thermostat Water Pump

see video attached

1968 evinrude lark x tank run - YouTube

 

[gusthewonderslug]

Re: 1969 Lark X 40hp Pee hole/Thermostat Water Pump

1968 evinrude lark x short pan - YouTube

 

[HighTrim]

Re: 1969 Lark X 40hp Pee hole/Thermostat Water Pump

First check compression, should always be step 1.

2. Have you gone through the ignition? Are the coils original ? Points gapped and clean?

3. There is an air leak somewhere in the fuel system, be it a fuel line, connection, carb restriction, causing the lean sneeze.

 

[gusthewonderslug]

Re: 1969 Lark X 40hp Pee hole/Thermostat Water Pump

Ok
I've checked the compression and its balanced at 120 on each pot.
Checked all the carby bolts etc, I will replace the fuel lines as they are a bit sus.
the points are clean but one coil is old.
I pulled the lower leg off and replaced the water pump impellor and housing to see if this improves the water flow, my question is how should the shift wires be sealed where they penetrate the leg, I have greased the area but not sure if this is sufficient to seal the area.
Gus

 

[Daviet]

Re: 1969 Lark X 40hp Pee hole/Thermostat Water Pump

It should be a friction fit, grease the wire loom when you pull it through and it should be good.

 

[gusthewonderslug]

Re: 1969 Lark X 40hp Pee hole/Thermostat Water Pump

Ok
I've checked the compression and its balanced at 120 on each pot.
Checked all the carby bolts etc, I will replace the fuel lines as they are a bit sus.
the points are clean but one coil is old.
I pulled the lower leg off and replaced the water pump impellor and housing to see if this improves the water flow, my question is how should the shift wires be sealed where they penetrate the leg, I have greased the area but not sure if this is sufficient to seal the area.
Gus