1965 40 HP Lark 7 hard to start.

[elark7]

I have only had my Bass Boat out two times this year, using a Pontoon so all 6 of my children can go to the lake at the same time. Anyways I went out the other day and the primer bulb would not get firm. Motor started right up then stalled once in gear. It did this several times until it would not start at all. I gave it about thrity minutes while I trolled the bank then it fired up and ran good. The bulb never did get firm and squeezing it did not do anything. Drove aroud the lake fishing diff spots then went back to the ramp, after about 3 hours. Once at the ramp it would not start again. I know the pickup tube is fine in the tank since I have used it all summer on the pontoon. Could there be gremlins at the boat ramp messing with my motor? Seriously I don't smell excess gas nor do I see it dripping from the carbs. Could the pump be keeping enough fuel from getting to the carbs? Or should I just pull the carbs and rebuild them since the boat sat for 2 months. Thanks.

elark

 

[tashasdaddy]

Re: 1965 40 HP Lark 7 hard to start.

i would look at the carbs.

 

[mikesea]

Re: 1965 40 HP Lark 7 hard to start.

If it ran OK once it started in all speed ranges,I would think carb is OK.I'm thinking the fuel pump may have a bad diaphram.It could be allowing fuel to go through the port that gives the pulse to operate.You might have a bad squeeze ball,which I would change first,be sure the tank is getting vented as well

 

[elark7]

Re: 1965 40 HP Lark 7 hard to start.

I am trying to locate the kit or the fuel pump for this motor with no luck. So far I can't even track down a number. All of the web sights, here included, has 1960 to 64 then from the 70's up, skipping 1965 to about 1972. Several look like my pump but no one seems to have it. Any ideas on what to do?

elark

 

[F_R]

Re: 1965 40 HP Lark 7 hard to start.

Remove the fuel pump and look at the pulse hole in the backside while you squeeze the primer bulb. If the pump is bad, gas will squirt out the hole. If it does not squirt out, there is no need to mess with it.

If you have an aftermarket squeeze bulb, they have been known to fall apart inside. I had it happen to me.

 

[elark7]

Re: 1965 40 HP Lark 7 hard to start.

So I went to the lake to test the motor and work on it. I have several more questions before removing the motor to work on it. It started right up without doing anything, odd? Then it seemed to lop and hesitate on take off. At WOT it ran great, more speed then before. Idle was a little hesitant. I wanted to check for spark and my light would not work so I removed the top plug wire- motor died. Restarted fine. Removed bottom wire engine kept running. So I thought I had a bad plug, wire, points coil etc. Pulled the plug and had spark. Compression checked at 105 both cylinders. Is it possible that there is fuel only getting to the top cylinder at idle and then both at part to full throttle? If it is sucking some air between the bulb and tank would this cause these symptoms? I am going to replace the bulb and fuel line as it was making a hissing , bubbling noise while I was priming. The bulb got hard but the sound of bubbles is not normal. I also have an exhaust leak somewhere but I have yet to locate it. It fills the hood but with it off I do not see any smoke and have no bubles anywhere on the head when I put soapy water around gaskets and bolts. Thanks again for ideas and help.

elark

 

[elark7]

Re: 1965 40 HP Lark 7 hard to start.

I finally got time to replace parts on this motor. Put new primer bulb on it, no change, new fuel pump, no change, was going to rebuild the extra carb that I have when I came across a clearanced item at Wally world. Bought it for a buck fifty. Took it home put it on, bulb got hard, engine fired right up stayed running. Shut it off and it fired back up with barely a bump of the key. Waited a couple of hours and it fired up again with barely bumping the key. Part was the connector on the fuel line to the gas tank. It is also probably where the hissing and bubles were coming from. I checked the old one and it popped apart, letting the spring and check ball fly out. Went back to Wally world and bought all 6 that were left on the shelf. So problem solved on the cheap.

elark