1959 Evinrude Lark 35hp Backfire

[oldboat1]

Yeah, really not much to check -- if the type with a screen, can unscrew the screen and make sure there is no blockage. I would just do the primer pump test, and if that keeps the motor running I would figure on replacing the fuel pump diaphragm. It doesn't have to be holed -- can be old and taken a set (lost flexibility). Sort of like old boaters....

Not emptying the bowl would indicate a carb issue -- maybe a nozzle gasket if your carb has one, or maybe a vent issue (not feeding). That means pulling off the carb, soaking it and opening all passages, checking for assembly, etc.

 

[Kimberly80]

Check and see if your not missing the cam wheel that follows that the edge if the timing plate , I've gotten motors that were missing the wheel or have deep cuts in them, throwing my start-up or idle off

 

[F_R]

So, what are the needles pre-set at now? And is the carb throttle butterfly set to open when the mark on the cam aligns with the pointer (not the roller). Do you have it in neutral and throttle open as far as it will go (in neutral)?

 

[showngo2000]

I set the needles like this:
Carburetor Adjustments - Two Adjustable N/Vs)
(J. Reeves)

Initial settings are: Bottom high speed = seat gently, then open 1 turn out. Top slow speed = seat gently, then open 1-1/2 turns.


--The cam wheel on the timing plate is there, seems to be functional.
--I'll have to double check the throttle butterfly opening when the cam aligns to the pointer later today. I could use a little clarification on this one if you can help...

--It's in neutral, and throttled high as it will go in neutral.

 

[F_R]

Look to the left of the roller. See that pointer sticking up from the intake manifold? As you advance the throttle control, carb should just barely start to open when mark on brass cam is aligned with the pointer.

 

[showngo2000]

No Title

Look to the left of the roller. See that pointer sticking up from the intake manifold? As you advance the throttle control, carb should just barely start to open when mark on brass cam is aligned with the pointer.

Yes, this is how it's working. When the pointer is aligned with the mark on the brass cam, the carb barely starts to open. I snapped this picture, too. It looks like there may be some missing linkage that goes from the roller to somewhere? There's an empty bracket (with the hole) coming off the roller...should there be something attached here?

 

[showngo2000]

Did some work today. Rebuilt the carb with a kit and started the motor. It fired for about 5 seconds and died. I checked the fuel primer bulb after that and it didn't stay tight...I puffed it a few times, and the exact same thing happened. The fuel filter bowl isn't being emptied at all. Sounds like a fuel pump re-build might be needed?

There's fuel being sent to the carb. When I took it apart, the carb fuel bowl was full. The carb was pretty clean, and not much buildup to speak of.

 

[showngo2000]

[No message]

 

[oldboat1]

Good point on the fuel filter bowl. There is a filter up there. Additionally, the bowl seal can be an issue.

Don't break the bowl, but might help to pull it apart and check it. Upon reassembly, a little gasket sealer around the lip of the bowl might help.

 

[oldboat1]

i.e., pump filter bowl. I missed your earlier reference to the pump bowl, thinking carb. Sorry. The filter and gasket are available. Thinking the filter is perforated plastic -- have a fuel pump kit somewhere with one. See if the filter is blocked -- can probably operate without it to test.

 

[lindy46]

Almost sounds like there is a short somewhere grounding out the motor and shutting it down. Check mercury switch, cut-out switch and kill switch circuits.

 

[showngo2000]

Got the bowl cleaned, and installed a new filter and gasket. No difference in getting it to run.

 

[oldboat1]

Tough case! Could be an ignition issue, as has been mentioned, but.....

pump kit is 18-7801 (Sierra): http://www.iboats.com/mall/partfind...gd_poid=109271&gd_row=44&session_id=146600495 .

 

[showngo2000]

I got it! Thanks to all of your help! The throttle linkage bracket was broken. Every time the engine would start, the vibrations would cause the linkage to shift and initiate the mercury kill switch. I got a spare bracket, and the thing started right up. I've got to find a tub with water to dunk the engine in to do some further testing. Thank you everyone!

 

[oldboat1]

Hey -- Well done! :thumb: