1985 Johnson 140 losing power

Fishin Dan

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Joined
Jun 20, 2005
Messages
8
About 4 months ago I bought a motor from a guy on craigs list. He started it up for me and did a compression check---all good 120 per cylinder. I put it on my boat and off I went, sort of. When I shifted in reverse to get off the dock, the boat went forward, and of course when I shifted in forward I went in reverse. No I did not have the cables hooked up backwards. Is this a counter rotating lower unit?? I swapped it out with another lower unit that I had from one of my 1st 3 motors, this is my 4th in as many years. I'm hell on these things for some reason. Anyhow after I changed-out the lower unit all was good for a month. Now it starts fine on the hose, goes into gear and rev's up great, once in the water it starts fine but will not rev up or get on a plane. I thought it may be a fuel problem so I put a new fuel line on it and removed cleaned and replaced the carbs. (which were spotless) however it still has no power in the water and uses alot of gas. This motor also has a electric fuel pump whitch seems to pumping gas alright I also have good spark on all 4 cylinders and new spark plugs What else should I be looking for??? Please help with any info Thanks Dan
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: 1985 Johnson 140 losing power

compression #'s? why electric fuel pump? clogged carb, what do the plugs look like after running.
 

Fishin Dan

Cadet
Joined
Jun 20, 2005
Messages
8
Re: 1985 Johnson 140 losing power

The fuel pump was on it when I bought it, 2 weeks ago comp aws 120 on all 4 cylinders. Ijust replaced plugs --maybe 20 minutes of run time I/ll check them after work today I changed carbs to one I know is good but still have same problem gotta go now damn job thanks Dan
 

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: 1985 Johnson 140 losing power

Is the fuel pump electric? If its the one on the engine it is a VRO with wires for an alarm system-its mechanical.

You are probably dropping a cylinder under load. Do a spark test and a compression test with all of the spark plugs out on both tests. Let us know what you find.

The 1985 and up 140 engines are true 140HP. The older 1983 pump for the crossflow is inadequate. You either would have to use dual conventional lift pumps, or buy the VRO look-alike for premix.
 
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