Johnson 140 STILL "bogging down" past 1/2 throttle

[imported_skeeter1]

I have put all new carb kits in again, as I found some of the mounting gaskets had been pinched - thinking maybe they were sucking air. replaced all gaskets, needles etc - test ran - ran like a champ for 6-7 wot slams from idle, then back to her old ways of bogging down past 1/2 throttle like it is flooding out
what have I missed?

 

[clint]

Johnson 140 STILL

Johnson 140 STILL

Is your choke sticking? If it is flooding out then your igniton might be failing some where. What checks have you made? Let us know. If air is sucking through then you would be starving for fuel.
Clint :$

 

[R.Johnson]

Re: Johnson 140 STILL

Re: Johnson 140 STILL

Have you done a compression test, make sure the engine is sound before replacing part's.

 

[Boilermaker]

Re: Johnson 140 STILL

Re: Johnson 140 STILL

Next time it bogs, try hitting the choke switch for a second...this will do one of 2 things...stall the engine if it was already too rich...OR allow the rpms to come back up for a second, if you were running lean during your bog (my bet is your lean).
If your main jets are partly clogged ( I know you just rebuilt...but you might have some varnish in the gas or other fuel problems) & you hit the choke...it could clear the jets hitting the choke at full throttle ( it causes a high vacume at that time & the jets are at the bottom of the fuel bowl).
BE VERY CAREFULL if its running lean...thats the quickest route to a blown powerhead!
Check your sparkplugs after the next "bog"...if they are dry with a whitish look...your running lean!!!
You mighty want to check your fuel line to the tank, including pulling the pickup tube in the tank...most have a screen on the end that can clog.
good luck

 

[marelcon]

Re: Johnson 140 STILL

Re: Johnson 140 STILL

My 89 Evinrude 100XP does exactly that - bogs past 3500RPM but perks right up when I hit the choke.

I'm thinking of a carb rebuild and new fuel line & filter. Getting the carbs synched again has me concerned though - I hear it's a royal pain... :%

 

[imported_skeeter1]

Re: Johnson 140 STILL

Re: Johnson 140 STILL

boilermaker, you are correct, when I hit the choke it perked right up for a second then back down again after I let off the choke
will blow out jets and pull pick-up out of tank
it has new primer bulb and new fuel pump diagphram kit alsothanks alot for all the help guys!!!!

 

[Boilermaker]

Re: Johnson 140 STILL

Re: Johnson 140 STILL

Dont forget to check the "SIMPLE THINGS"...like making sure the fuel line isn't pinched somewhere. Also make sure you check the tank vent & vent line!
I had an engine that refused to run after 2 minuits...it was simply a slight sag in the vent line...Gasoline sat in there from a fillup and it acted like a seal. the vent line hung down like a U shape...but only an inch or 2...that was enough to seal the air off & the fuel pump couldn't pull fuel from the tank....MY point is check EVERY LITTLE THING!
Good Luck

 

[alaskageorgephipps]

Re: Johnson 140 STILL "bogging down" past 1/2 throttle

Re: Johnson 140 STILL "bogging down" past 1/2 throttle

ive got a 1984, 140 with the same problem. ive installed new coil packs, and a new power pack to the side with no spark.the wiring seems to be ok so i dont know where to go next. anyone got any suggestions?

 

[ezeke]

Re: Johnson 140 STILL "bogging down" past 1/2 throttle

Re: Johnson 140 STILL "bogging down" past 1/2 throttle

To alaskageorgephipps: the 1984 is a crossflow, the 1986 is a looper, so they are different systems. It would be helpful for you to start a new thread. See "New Posts" at the top of the page.

 

[Robbiecd]

Re: Johnson 140 STILL "bogging down" past 1/2 throttle

Re: Johnson 140 STILL "bogging down" past 1/2 throttle

I have a 1986 140hp v4 Johnson with the same issue. There HAS to be someone out there who knows what this is from experience with similar engines with the same problem, I'm getting frustrated with all of the "test every component first, then I'll tell you" replies.

Please let me know if you solved this problem.

 

[BonairII]

Re: Johnson 140 STILL "bogging down" past 1/2 throttle

Re: Johnson 140 STILL "bogging down" past 1/2 throttle

I have a 1986 140hp v4 Johnson with the same issue. There HAS to be someone out there who knows what this is from experience with similar engines with the same problem, I'm getting frustrated with all of the "test every component first, then I'll tell you" replies.

Please let me know if you solved this problem.

You're replying to an old thread...which is frowned upon. Start a new thread and we'll be able to help you.

BTW: Most here ask for the poster to check certain components systematically so they can give you sound advice. If you haphazardly just start replacing parts to try and fix a problem, you'll spend a lot of money and still not be guaranteed to fix the issue.
Trying to take a shortcut normally ends up costing you more time and money than troubleshooting the CORRECT way.