1974 70 hp

[stevenmrob]

i bought the boat and motor and the guy told me it has no throttle past idle. got it home and put new gas and oil at 50:1 and after idling for a while got all the old gas out of carbs it idles great. when you hit the throttle it instantly dies like you turned the key off. if you bump the throttle up a little at a time it tries to come up but stuters and if i pull throttle back it stratens right out. My first time working on a motor and was wanting some ideas on what to check before it take to mechanic.

 

[stevenmrob]

Re: 1974 70 hp

i forgot model number is 70esl74m and its a johnson

 

[KLINDWW]

Re: 1974 70 hp

I would start by taking the carbs off and cleaning them. It sounds like maybe this motor set up for some time with gas in the carbs, when you said that after idling for a while and all the old gas got out of the carbs. Also you might run a compression test, just to make sure that the motor is a good one, so we can eliminate that.

 

[stevenmrob]

Re: 1974 70 hp carb problems

Re: 1974 70 hp carb problems

well i just pulled carbs off and bottom carb jets were plugged but also noticed that float needle was a little sticky on bottom two carbs. cleaned everything out and reassembled. left plug out where high speed orifice was (call it a hunch) and started priming the bulb and gas was only coming out of top carb; none out other two. is it possible that it will run off one carb for idling and is that a good indication that i need to replace everything in carbs instead of just clean them.

 

[KLINDWW]

Re: 1974 70 hp

I would definitely suggest the rebuild kits but to be honest the only internal parts that get replaced are the needle and seat. Most of the rebuild kit is the gaskets. You will be reusing those jets anyway. That motor will run on one cylinder, I have proven that with mine, but I think that you may be looking at it backwards. When you pump up the bulb, gas should not come out of the carburetor anywhere. The bulb should pump gas into the bowl until it is full and then the needle should seat and the bulb should get hard and shut off the flow of any other gas to the carb. If you have gas coming out of one of the carbs the needle is not seating off and that carb is probably flooding. One other thing would be to check the float, I had a float one time that had a small pin hole in it and would not ?float?. You might want to get the floats when you get the rebuild kits. Sounds like you are on the right track with the problem being in the carbs though. Don?t forget about that compression test though. That is always good information.

 

[stevenmrob]

Re: 1974 70 hp

found the prob. the bottom two carbs were not getting any gas cause float needles were sticking closed. didnt have rebuild kit yet so took them out just to check and runs like a champ now but floods when idles but that will be fixed when i get rebuild kits. my carbs have a drain plug in them to drain the gas for storage.