1976 Johnson 135hp, fuel problem

[jhouse]

my 76 Johnson keeps gushing fuel and collecting in the cowling, it looks like its coming out of the air intake of the bottom carb. it is extremely hard to get started. once i get it going it runs superbly, but if i let it sit for a while and fish with the trolling motor for more than about 15 mins. it is hard to start again and acts like its flooded. I have changed the needle and seat and it "seemed" to work for a while but now its doing the same thing. why is it gushing fuel and so darn hard to start ? but like I said once I get it going it runs great, but I have to start it every 10 mins. or so to keep it from flooding. Please help. Thank you

[emdsapmgr]

It's not unusual for these early crossflows to leak a little fuel out the carbs, esp if you tilt the engine up while fishing with the trolling motor. The excess fuel will pool in the bottom of the airbox. Normally, there is an airbox drain hose connected to the bottom cylinder of the engine-to recirculate that fuel back into the engine. When first started, that excess fuel may seem like the engine is flooding (excess smoke) for the first minute or so, till that excess fuel gets burned off. Make sure that hose is in place-it's messy without it.

[adamh1281]

I agree, but also try removing the carb and turning it upside down, and blowing with your mouth into the fuel intake line, it should allow air in while upright, it should not allow air into while upside down. I would also remove the float, and make sure it is boyant. it may be sinking in the gas, not allowing complete closure of the valve. I had a truck with a copper float, and it was welded with what looked like lead on a seam, well the seam leaked, and the bowl would overfill. check the height adjustment on the float also. Gaskets may also not be properly aligned. I am not familiar with your specific carb but this may help.

[jhouse]

the airbox drain is in place, but im missing the airbox gasket. i made my own with some fuel resistant gasket material but it doesnt fit quite right. iwill take the carbs off again and see if the needles and seats are closing properly. the last time i had the carbs off i did check the float position by turning the carbs upside down to make sure the floats were parallel with the bowl. they looked like they were in position. but i didnt blow in the intake to see if they were seating good. But why is it so hard to start after it sits for 15 minutes or so ? my new battery is almost toast already. thank you for your help.

[jhouse]

I guess its like every other two stroke engine ive ever owned, if it doesnt start right up during cold start procedure it means the plugs are fouled. In the case with my Johnson they are fuel fouled due to excessive cranking and pumping fuel into the cylinders (especially on the lower cylinder banks).......SOLUTION : always have a dry set of plugs to install if she doesnt fire on cold start the first few cranks. My KX 250 was the same way. Thank you emdsapmgr & adam for your responses, Im on my way to the river to slay the smallies !!!!!

[BonairII]

I guess its like every other two stroke engine ive ever owned, if it doesnt start right up during cold start procedure it means the plugs are fouled.

If the plugs get so-called 'fouled'...are they actually ruined that quickly?? I've experienced some "hard starting" lately and have had to crank the motor quite a bit, and once it starts up it runs beautifully.

[jhouse]

I have the same problem. My engine will start if i crank and crank and CRANK some more. but to save my battery and starter ive been swapping out plugs. To answer your question........no the plugs arent actually "ruined" they just need to be dried out. So I always have a dry set of plugs with me. BTW what kind of outboard do you have ?

[laotou]

Same here. Mine is 76 85HP Johnson O/B. I cleaned all plugs between uses with Seafoam and let them dry. I always have a set of dry plugs on the boat. If the engine can start in the second try, it is my lucky day. I don't expect it to be as good as my 2011 car. Come on, it is the technology 35 years ago.

In cold start, I always take off the cowl and lift the warm-up lever. Make sure that the "Start" mark on the throttle cam points to the center of the throttle cam roller. It helps a lot.