1975 50HP Starts great but dies in gear

[SBoulden]

Ok so I have 1975 Johnson 50 HP and it starts good but when I put it in gear it slowly dies, plus it seems the engine in spiting gas into the lake from the exhaust. Im hoping this is a simple problem? Any ideas please let me know cause im not very familiar with boat motors yet.

 

[marko shark]

Re: 1975 50HP Starts great but dies in gear

i have the same motor as yours you will find two black plastic caps on the front of you motor under the cowling where you can adjust the idle your motor wiil stall in gear if these are out .start your motor (in the driveway) and tune them left or right until corrected.as for your fuel leak i suggest keeping an eye on your male/female couplings on your motor.

 

[tashasdaddy]

Re: 1975 50HP Starts great but dies in gear

i've had a lot of these motors, check your compression, spark on both cylinders, will run on only 1, carb idle adjustments, (see Faq carb adjustments), idle speed adjustment screw, on throttle linkage. these must be set with the boat in the water and IN GEAR. you can get it close(higher) on muffs, but must be fine tuned in the water, where there is backpressure on the exhaust system.

 

[SBoulden]

Re: 1975 50HP Starts great but dies in gear

Ok so I checked the spark and each cylinder seems to have good spark, I ran it today and still getting gas coming from the exhaust. Is this a timing issue or fuel issue or no idea? Im real stressed, it also seems to run choppy if I turn down the High Speed idle it sometimes with die but not right away.

 

[1730V]

Re: 1975 50HP Starts great but dies in gear

Your carburetors are fouled. They need to be disassembled and cleaned with new kits.

It's easy on that engine.

 

[SBoulden]

Re: 1975 50HP Starts great but dies in gear

but if thats true why is the gas coming from the exhaust?

 

[F_R]

Re: 1975 50HP Starts great but dies in gear

If you are actually getting gas from the exhaust it is because you are dumping too much gas into the cylinders. That is referred to as running too rich. It slobbers around and doesn't burn it all and what's left runs out the exhaust. The causes are many, from simple carburetor mis-adjustment, to leaking float valves, to a ruptured fuel pump diaphragm, to insufficient spark or bad plugs, to powerhead damage.

 

[tashasdaddy]

Re: 1975 50HP Starts great but dies in gear

becuase your float needle is not closing, giving the motor too much fuel. you need 2 carb kits, complete cleaning including removing and cleaning the high and low speed jets. you need carb tool 317002, most of us made our own from a screw driver. i made mine with a belt sander.

 

[SBoulden]

Re: 1975 50HP Starts great but dies in gear

Ok well i will check into that but for the record I didnt a Compression test on it today and top cylinder had 150 PSI and the Bottom has 145 PSI this I assume is good. I also checked and I do get spark, but I changed spark plugs today to be safe and now it wont run at all, so I put the old ones in the see if it would start and still nothing. Now im at a total loss I have no idea whats wrong so I might take it to get looked at but I cant find anyone who is willing to work on this old of motor :-(

Plus when I bought that motor a week ago the guy told me it had a new fuel pump and clean carbs. I guess maybe he wasnt being 100% honest.

 

[HighTrim]

Re: 1975 50HP Starts great but dies in gear

Have you checked spark after changing the plugs and having it not fire? Is all spark gone? Disconnect the black yellow stop wire and retest. If the engine's ignition has spark, the stop circuit has a fault-check the key switch, harness and shift switch. The kill lanyard isnt out is it?