My buddy bought a motor through a friend of a friend 2 years ago and started having an issue with it at the end of last season. It is an older Johnson 25HP tiller and it runs fine at half throttle, but when he tries to "open it up", it sputters, but stays running. Does anyone know what might be wrong with it? He said he ran seafoam through it at the end of last year, but that didn't do anything for it. I was just trying to see if there was anything he could try without taking it in and having to pay someone right off the bat just to look at it. Thanks from him in advance.

Sounds like only the idle circuit s providing fuel. You prolly could rebuild the carb yourself.

Thanks for the reply. I will pass on this info to him, but knowing how he is, he will just take it to someone to get it fixed rather than trying to fix it himself. I looked at the motor section of the site and it looks like there were a couple of things he might try first like change the sparkplugs and get a new tank and hose. If these don't work, then I'm sure he will take it in.