25hp wont run WOT

[limabean]

Guys,
New to the site and have read a lot of good info here. I have a 79 25hp johnson that idles great and will run partial throttle but when opened up it revs up then bogs down, you can let it idle for a minute and try again with same results. I have rebuilt carb, new tank and hose. tried squeezing bulb when bogging starts and it makes no difference the bulb gets hard, took the pump apart and the diaphram seems stiff but don't know if that is normal. It acts like it is starving for fuel but when I squeeze the bulb it doesn't help so doesn't make much sense to me. Motor is a 25r79r. Any ideas or suggestions would be appreciated.

 

[Cofe]

Re: 25hp wont run WOT

You say that you dissembled the fuel pump. The fuel pumps are difficult to get back together right, took me two tries even with a new kit and instructions. Many people purchase a whole new pump instead of messing with the guts. "The diaphragm should not be stiff"

It could be that your carb float needs adjusting. See the top secret file in the forum. Hope this helps ya

 

[limabean]

Re: 25hp wont run WOT

Thanks for the reply. I took the pump apart after the last time I tried it in the river so I hope I haven't added to my problem. I did adjust the float when I rebuilt the carb with carb upside down float is basically level with carb casting. I went to a dealer today to pick their brain and the guy there told me I must remove the high speed jet in the bottom of the bowl to clean it, he also said there was a tube down there by the jet that should fall out but it usually is stuck in there. I didn't have a screwdriver that would fit so I bascially scraped the crud out from down there and made sure the hole in the jet was cleaned out. Does it sound like the shop mechanic knows what he is talking about?

 

[Cofe]

Re: 25hp wont run WOT

Scrape crud with a screwdriver on the highspeed jet

Sounds like you need to do a proper carb overhaul. You need to get a jet removal screw driver to do the job right. A regular screw driver will almost always damage a jet.