35 horsepower dies when accelerating

[jturner]

Has anyone ever had a problem with the Johnson 35 horse, 3 cylinder motor. I bought it in 1995 and it has been a good motor up untill now. My nieghbor has the same one and has been out of commission for over a year with his. Mine just started acting the same way. After running for a few minutes and then stopped for a while, when started and given a bit of throttle it dies like a dog. I've put a new thermostat, water pump (third one), new plugs and gas filter and rebuilt the oil sending unit. recently. It won't take the gas any more than half throttle, misses a couple of times and then dies like turning off the ignition. My nieghbor has had his to every shop in town to no avail, even had the REP down and they can't pin it down. Is there someone who can help me on this problem. THANKS --jturner

 

[JB]

Re: 35 horsepower dies when accelerating

Ahoy, JTurner. 'Could be a lot of things. Let's narrow it down.<br /><br />1. Is it a fuel starvation problem?<br />Take her out and get her to misbehave. When she wont start, spray WD-40 into the carbs. If she fires up, it is fuel starvation. Most likely culprit: fuel pump. Other suspects include fuel tank venting, fuel tank anti-siphon valve, cracked fuel line sucking air, failed primer bulb valves.<br /><br />2. Is it an ignition problem?<br />While she is refusing to start, pull each plug wire in turn and see if it will shoot a 1/2" arc to the block. No fire? Power pak is prime suspect. With engine cooled down and willing to start put a hair dryer on the power pak and heat it up, then try to start her. <br /><br />3. Is it a flooding problem?<br />If neither of the above yeilds useful evidence, check if your engine controls are trying to choke or prime the engine after it is warm and flooding it.<br /><br />Let us know what you learn from the above.<br /><br />Red sky at night. . . . <br />JB

 

[kalloway]

Re: 35 horsepower dies when accelerating

Water in the gas tank can give similar symptoms. Does you filter separate water?

 

[jturner]

Re: 35 horsepower dies when accelerating

Thanks for the help guys, but I tried it again today and found out that it starts the first time, then it will run forever if it isn't shut down. If it is stopped for 5 minutes, thats when the little critter developes a slight miss then on acceleration will die. If I baby it for a few minutes, it seems to snap out of it and run again untill shut off. The thing is not hard to start. In fact it will start right up, it just won't stay going when a load is put on it. You know, I've had Johnson motors all my life- 59 years and this one is by far the most tempermental. I think I can see a 4 stroke in my future, but I would sure like to wear this little puppy out a bit first. It could be gas, but the way it shuts down is like turning off a switch. Could it be the power pack, or is there a swich shorting? What about the kill switch there on the handle? Why does the sucker only do it after it has been shut off once? Nothing is ever simple, right guys?? jturner.

 

[arimarks]

Re: 35 horsepower dies when accelerating

Hi jturner,<br /><br />I have exactly the same engine and exactly the same problem!!<br /><br />Did you find out what was causing this as it is driving me up the wall as well.