Hi. My father is giving me a Johnson 9.5hp motor that he has owned since basically new. Since I dont have it yet, I am not sure what the exact year or model of it is. All I know is that is comes with the shaft extension, it a 9.5hp, and it is late 60s or early 70s. This motor ran like a top since he has had it. 2 pull kind of motor. It was in storage for probably 15 years (early 80s to mid 90s) and when we took it out to use it, it ran like a top (we had the carb cleaned and had it checked over, just to make sure) we used it for 3 summers, and then suddenly, we took it out one day and it would start and idol fine, but as soon as you open the throttle, it would die. We checked the fuel line, o-rings (a problem that he used to run into was if there was a nick in one of the o-rings, it would suck air and not run) and anything else we could find, but we are stumped. Anyone has any suggestions where to start. Also, we want to put the shaft extension on it. Just wondering if there are any tricks to this that I should know about. I havent looked at it yet myself, so any tricks anyone knows about, I would be glad to hear. Thanks.
<br /><br />Try it with the bonnet off, radioman. Those engines sometimes get an exhaust leak under there that strangles the engine.<br /><br />Also try squeezing the bulb while it is trying to die, and squirting some fuel mix into the carb.<br /><br />Sounds to me like you may have a gummed up high speed circuit in the carb, but try the above stuff first.<br /><br />Good luck.