1987 40hp Johnson. Starts, idles, wont open up

travissheerer

Recruit
Joined
Mar 19, 2011
Messages
2
The motor starts great, idles great, will run at low speeds (under 5mph), however, when I give it any more throttle starts chugging and bogs down but stays running and just keeps chugging until put into neutral. Carbs and Fuel pump new two years ago and the fuel pump is not factory as the mechanic took the oil injection out and is now mixed with the gas. I took the fuel pump apart and all the gaskets and parts look good. This started the day after a really rough ride on the Detroit River. Don't know if that would have anything to do with it or not. Getting good spark. Any suggestions? Thanks

Additionally, when this issue first started last year the motor would run great for 5-10 minutes wide open, before just cutting out instantly and start chugging. Now it won't let me throttle it up at all before bogging down. Also new coil last year.
 
Last edited:

cr2k

Captain
Joined
Mar 19, 2009
Messages
3,730
Re: 1987 40hp Johnson. Starts, idles, wont open up

Sounds like your high speed circuit is clogged. A prime suspect is the emulsion tube.
 

travissheerer

Recruit
Joined
Mar 19, 2011
Messages
2
Re: 1987 40hp Johnson. Starts, idles, wont open up

Thanks, and while I was doing what you said I noticed the wires on the back of the fuel pump and followed them to the connector and they were not connected. Do you think this could be the problem? I don't know what the function of those are. Thanks
 
Top