1964 Lark cooling at high speeds?

[carsonf]

Wow! Great site! I've recently purchased a lark 4. I have changed the impeller as per instructions in previous posts... (manual is in the mail). It has a good amount of water discharge at idle and lower speeds but when accelerating at higher speeds and staying there no water is being discharged and air is actually being sucked in the outlet. When decelerating the water starts to flow again but is very, very hot for awhile. Is this normal? Thanks for your help as I couldn't find anything relevant in previous posts.

- carson

 

[F_R]

Re: 1964 Lark cooling at high speeds?

Air being sucked in the outlet is a new one on me. But, I wonder...is the thermostat in place? Especially the thermostat plastic housing and relief valve? It won't work right without those parts.

 

[carsonf]

Re: 1964 Lark cooling at high speeds?

Ok, ordered the thermostat kit. Looked at the motor again today and the thermostat and rubber housing are intact and it opens properly on the stovetop. Decided to compression test and both cylinders are just above 90psi. Started it up in the barrel and got good water output. Got in the boat and wouldn't you know just below and behind the carb are two bolts missing with a good amount of exhaust coming out!? Going to fix that tommorow and then out to the reservoir...

 

[carsonf]

Re: 1964 Lark cooling at high speeds?

I have the new thermostat in however it came with a rubber grommet of some sort. Mime didn't have this prior and I can't seem to place it either above or below and still fit the cover back on. Havnt taken it out yet but any other ideas? Btw the new thermostat fits as it should just like the prior one. Any ideas???

 

[kfa4303]

Re: 1964 Lark cooling at high speeds?

Hi carsnoff. The t-stat just drops right into the o-ring, then the whole thing drops into the t-stat housing. Here's a pic that may help.

http://www.iboats.com/mall/partfind...gd_poid=111071&gd_row=12&session_id=358351540

 

[HighTrim]

Re: 1964 Lark cooling at high speeds?

First thing to install is the spring, followed by the pressure control valve (white plastic disc), then the t stat housing gasket, the t stat housing, then the t stat, then you bolt on the t stat cover with gasket.

 

[carsonf]

Re: 1964 Lark cooling at high speeds?

Ok, so im a newly at this. Originally took off the stat cover and the old thermostat lifted out very easily. When I got the new kit recently it came with the what appears in the above link photo. My old one never had this rubber piece. I installed the thermostat with rubber gasket as shown but the stat cover didn't simply fall into place as previously. I tightened it down and tue stat gasket is tight. Is this correct?
As per the previous post it appears that all that was mentioned is already there. With the thermostat out I can see a white plastic disc/ball that mist have a spring below it. The stat housing os there also. So... could missing this rubber piece for the thermostat have affected wot water being displaced and actually air being sucked in the outlet? Hard saying not knowing...

 

[carsonf]

Re: 1964 Lark cooling at high speeds?

Any help? The parts diagram I have doesn't use the gasket around the stat in the link above...