Wednesday, July 19, 2017

Sneak Part-II, the carburetors!

Maiden voyage of the LMS Hazel - that would be: Lake Mildred Ship - Hazel... got delayed with a little loop through the workshop to rebuild the dual carbs.  So, launch is delayed with travel and other things for a couple of weeks.  In the mean time here are a few engine pics for the motorheads out there!

These are 1960's vintage carbs.  A little cleaning and they will hum like new!  Let's not discuss fuel efficiency or emissions though!  This little V-4 is a thirsty little engine, but a very reliable little mill.  It amazes me to think these 57 year old motors are still out there chugging along. The '64 that pushes our classic is a roller bearing motor!  So fuel to oil ratios went from 30:1 to 50:1 in '64 when this motor left the factory. This show was a big hit when this motor was new! 

Today the fuel pump, maybe this weekend I'll get to the carbs.  One bad thing about modern fuel is the introduction of ethanol.  That stuff is hard on some rubber seals and it actually dissolves the shellac off of the cork floats used to meter fuel in the carbs.  So the cork floats sink!  After cleaning the carbs the floats will get a thin coat of gas tank sealer.  Just in case some ethenol gets in the tank someday. All fuel lines will be replaced with ethanol friendly chemistry. 

On way to dockside to see how she runs... We're looking for the fiberglass back seat that was an option back then, and I'd really like to get the interior upholstered in the period correct style this winter. 

What a beautiful boat...  She's a Larson All American, made in 1959 and this sleek little gem might have been towed to the lake behind one of these...  This pic is of Lake Mildred, and  our dock is on the side of lake... It was easier to use the public ramp to test out the motor, so off we went...

After a little testing it was clear that we couldn't pull power at the ramp, these dual carbs were a little gummed up. One very interesting feature on this dual carb set-up is the mechanical synchronization of spark timing with a rather complicated linkage that advances the distributor with increased fuel demand.  Really very cool. I can imagine the engineers around 1960 when this engine first appeared doing dyno runs to figure out how the cam profile needed to look in order to maximize power output!

SO time to go through the fuel system... I started with new fuel, then worked my way through the fuel pump... This is a common crankcase diaphragm pump.  Differential pressure in the crankcase created by the 2 stroke cycle cause a spring backed diaphragm to flex and push fuel through a check valve pair.  Pretty common for the era.  Makes good pressure - more than the carbs can draw. Luckily for us in 2017, the check valves were immune to corrosion or fatigue.  Way to go 1960's engineers!  You sent Apollo to the moon with slide rules - that generation of men and women of science rocked!

Some deposits... a little oil separation too.  Parts clean up is going well, the pump looks like new now!  It may be a few more days to get to the carbs... The white stuff is oxidation from trace amounts of water in the fuel reacting with zinc in the casting... It has to be abrasively removed to clean it out.  Not too bad for 53 years of service!

A very fun work in progress,  the '47 Studebaker is on hold this summer  but I'm going to do my best to get the engine rebuilt this fall though!


No comments: