Help with 1960 Jonny 40 hp choke

Just got a Jonny 1960 40 hp super-quiet, I want to by-pass the whole, water-exhaust heat-over-engineered auto choke system & just use the manual choke, my question is what is this best way to do it? Also there is one hose going from the choke to the intake what is its function? thanks

Re: Help with 1960 Jonny 40 hp choke

Those things rarely worked right when brand new. Many (most) people simply used the manual override. No need to do anything with the automatic one, just leave it. It will be there for the next owner to cuss.

The vacuum hose is an "unloader". It partially opens the choke when the motor starts. Otherwise it would continue to run on full choke and flood out. It takes a few minutes for the heat activated part to warm up.

Re: Help with 1960 Jonny 40 hp choke

I want to unhook it mostly so I don't have hoses running everywhere + just to look a bit more tidy, Also don't like the idea of warm seawater heading to my carb, Must of been a slow week for the engineers. Other than the over engineered choke, it looks like a real nice motor.

Re: Help with 1960 Jonny 40 hp choke

My dads 1963 40hp had the water heated choke. It worked without a hitch.

Re: Help with 1960 Jonny 40 hp choke

I thought the 63 was only exhaust heat not the water heat? the 1960 from what I have been told was the only year that had both exhaust heat & heated water operating the choke but I very well may be wrong, I'll have to check my 10th edition either way I want to remove all the hoses plug the nipples and loop the water nipples to just circulate through themselves, and operate the manual over ride as the only choke. I know this topic has come up before hope some who have done similar will set me straight!

Re: Help with 1960 Jonny 40 hp choke

What we are dealing with here is a bit of information and a lot of misinformation. If I may set the record straight:

The automatic choke first came out in 1960 on the 40hp and 75hp Electric start models. It was strictly water heated---no exhaust heat about it. The water heats the choke body and bimetal spring to open the choke when the engine warms up. A vacuum diaphragm partially opens the choke as soon as the engine starts to prevent flooding. A manual override on the other side permits settings of choke off, automatic, and choke on. There are 3 hoses, one bringing hot water from the cylinder block, another sending it on to the return water tube back to the water pump, and a vacuum hose to the intake manifold.

The 1960 choke continued to be used through 1963

The hot-air choke was introduced in 1964. There are no water connections to it, only a hot air tube coming from a heat exchanger in the exhaust manifold. Special passages in the carburetor and intake manifold create a low pressure to draw air through the tube. The hot air heats a bi-metal spring to control the choke position. The vacuum diaphragm is gone, and an electric solenoid is added. The bi-metal spring does not close the choke tightly enough for cold starting, so the flooding problem is greatly reduced. However, now there is a need for closing the choke tightly for cold starting-----the electric solenoid. In the 1964 models, the electric solenoid operated every time you started the motor (for truly "automatic" operation). That presented a problem sometimes when starting a warm motor right after shutting down and no choking was needed. So...an "override" switch was provided to allow the driver to prevent the electric solenoid from operating. That worked, but few people understood what the heck they were doing, so the override switch was soon replaced with a choke switch, which now meant the "automatic" choke really was only a "semi-automatic choke".

The hot-air choke worked pretty well and was used through 1970. 1971 models went back to electric chokes.

OK, with all that history, if you are bent on removing the hot water choke, go right ahead and do it. Leave the manual lever on the other side. You can remove all the hoses and plug the fittings. It will get along just fine without all that stuff.

Re: Help with 1960 Jonny 40 hp choke

Very good info indeed.

Re: Help with 1960 Jonny 40 hp choke

Thanks F R my main concern was the hose from the intake, Just was not sure if plugging it would cause bad things to happen.