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'61 Lark III Loads up/ floods at WOT

bdfwinn

bdfwinn

Member
Hi folks, newbie here. I am a pastor in Richmond VA andrecently a church member gave me a 1961 Chieftain with a Lark III 40hp on it.The boat was always kept under a shed and looks pretty cool. He gave the boataway because it had stopped running. I replaced all the fuel lines and rebuiltthe carb (I used to build small block chevys and have rebuilt numerous carbsincluding small engine and one 9.5 Johnson carb) So my frustration is thatthere is no way to externally adjust the fast idle valve and the engine runsokay at about 80% power for around 30 seconds and then the carb loads up andfuel spills out of the intake screen. Then I have about 1/2 throttle until theexcess fuel is burned and then we are good to go for another 30 seconds or so.Do I need a fast idle adjustment or is the new float and needle assemblymalfunctioning or in need of adjustment. If so where do I find thosespecifications.
more info: spark isstrong. Plugs are both fouled. Fuel pump seems okay (fuel bulb holds pressure)Idles okay but a little rough. Slow speed screw set at 1 1/2 turns out fromseated.
With the spark plugsout of the motor I can rotate the flywheel by hand fairly easily and I noticethat there is no movement on the bottom compression relief valve. Is thatnormal? The top one has about .030 gap or better.
Your kind help isappreciated.
Bill
 
The compression relief only works when using the manual / recoil starter.----------Plugs will foul if thermostat is removed and motor runs cold.
 
kimcrwbr1 said:
Sorry just to the left of the follower wheel is the pointer to adjust the sync between throttle opening and timing advance. I have a 61 lark III 40hp and put the float bowl off my old 57 35hp it has the high speed needle but not really necessary as long as you cleaned the high speed jet good it should be just fine.
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Thanks for all that info. I did not set the float at all when I did the carb because there was no gauge in the kit. I crossed my fingers and hoped the float that came in the kit was pre-set. I will check that.
 
Not that it is causing the problem, but that compression relief valve that does not have the .030" clearance, should have. At the least, it should not be holding the valve open at all.
 
Okay so I took the carb off again and the float seemed okay. I blew through the fuel inlet with the carb inverted and no air escaped. What I did find was that I had left the Fast Idle Screw all the way in so that it was completely seated. I backed it out 3/4 of a turn as per the manual I found online. Also, there seems to be a fair amount of exhaust inside the engine compartment. Could this be starving the engine of oxygen? How easy a fix is that?
 
Oops the high speed nozzle is what I backed out 3/4 turn. was that a mistake? Seemed a little weird but this being an OBM Carb I thought "oh well. Yep I goofed. Just checked with a manual I found at boat info.
 
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Okay I removed the carb AGAIN and screwed that nozzle back in fully and made a slight adjustment to the float. If this does not solve my loading up problem I guess I will have to open the fuel pump and redo the ignition. The fuel bulb maintains pressure when I squeeze it tight so that sort of tells me the fuel pump is okay. Am I wrong on that? Oh BTW I am in Richmond VA and below 500'
 
Eye bolt is the lifting eye. Also serves as the rear bolt to hold the recoil starter down. Having trouble referencing the length of the spring, but I think it is a recoil starter pawl spring.
 
fdrgator said:
Eye bolt is the lifting eye. Also serves as the rear bolt to hold the recoil starter down. Having trouble referencing the length of the spring, but I think it is a recoil starter pawl spring.
Click to expand...
Okay that makes sense because the recoil starter does not work. You can pull the rope and it will retract just fine but it does not engage the flywheel and turn the motor over.
 
Okay took the boat out today after church. The carb still loads up after a few seconds but it does seem to be idling and running smoother now that the high speed nozzle is screwed in all the way and the float is adjusted. When the engine was beginning to bog down I had may daughter squeeze the fuel bulb and that all but killed the engine. Fuel pump leaking fuel into the combustion chambers? Still need to check "sinc and link". Will keep you posted.
 
Took fuel pump apart. Pump diaphragm was okay with no holes. It had a bit of carbon on it so I cleaned it and put it back together. Also the small springs I found down in the engine well were from the recoil starter. The pawls and screws and such are missing all together. I am determined to turn this boat into a real blessing for my wife and daughters!!!! Underside of recoil starter.jpgFlywheel top.jpg
 
Obviously someone had difficulty understanding how to put it together and how to make that work.........Lots of used parts available for those recoils.
 
prop.JPG okay so here is the latest. I found a recoil starter for $20 that has all the parts and works. I have yet to take off the flywheel but will do that soon. (I have a funeral Friday and a Wedding to officiate Saturday). Here is a picture of the prop. It is a 10 3/8 x 14 according to the manual. part number 278194. Can I cut the other blades to match and balance the prop or am I relegated to finding a new one?
 
For that motor the 14" pitch is most you can get.--That would be for a very light boat.---An 11 1/2" or 12 " might be more suitable.
 
That would certainly be better for a 16' fiberglass boat.-------If the boat / load was heavy you might even want to go to less pitch.
 
Recent finds... The throttle will not advance to WOT now. I don't know what I did but it did fine until I removed the fly wheel. I was gentle in removing it. (I used a strap wrench and a proper wheel puller and it popped right off) The shift lever will not go far enough forward to let the shift lock to slip into the bottom slot in the shifter/ throttle lock out lever. Also the coils were apparently replaced in 1990. Should I take them off and check them or is there a way to test them. Also there is a collar on the throttle linkage that seems like it is doing nothing. Oh and by the way there is a pick of the timing marks with the throttle lever on the control unit all the way back. Throttle Control Collar.jpgTiming marks with throttle fully closed.jpgIgnition Top View.jpgShifter Lock.jpg
 
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okay the shifter issue is solved. Rotated the crank shaft a bit and she slipped right into place. Throttle stop collar now hits and stops the throttle from advancing.
 
Those coils should be good.-----You have to be carefull in adjusting that collar !---People often adjust that because it " looks wrong to them " when in fact it is correct.----Please read about that / search for info on that adjustment before doing anything with it.
 
Took off flywheel points look really bad. They were replaced in the 1990's and cleaned in '08 apparently. I will order new ones and new condensers but I cannot find spark plug wires. My parts manual lists the wires as 4 different parts and not as one thing. Anyone know where to get the plug wires for a '61 Lark 3?


Also an update on the carb. The new needle and seat/ float seemed a bit sticky to me so I took the seat out and put the needle in it and just rotated it by hand a while inside the seat and it seems to seal well and not stick. I put the carb on my work table and filled it with a hose and funnel and it did not flood out of the overflow or the carb body. That is great news.
 
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