1986 235hp Johnson strange bog down issue

stuee

Petty Officer 3rd Class
Joined
Jan 1, 2011
Messages
95
Hi all.
The motor was running perfectly well the other week then i took out lastnight. It was running ok for 5 mins then seemed like it was low on fuel.
The vent on tank was open and no restrictions i can see.
I run half throttle all the time as thats about 70k on the water but i had to put full throttle and i could jog faster.
It almost stalled a few times too.
The warning horn didnt sound nor did the pee stream stop flowing.

The funny thing was we stopped to fish at a spot for 3 hours then when started it again i got all the way back half throttle and normal speed without any problems?

Any idea what could have caused this?
 

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
Joined
May 19, 2001
Messages
26,019
Re: 1986 235hp Johnson strange bog down issue

Could be a power pack that is starting to go, could be crap in the fuel, a fuel pump going bad, could be a dozen things..........

You really have to start from the beginning. Compression, spark, when was the most recent carb overhaul, use the cdi troubleshooting guide Technical Support | CDI Electronics for the electronics.

Sorry, there is no short answer for that so you have to play detective by the numbers.
 

stuee

Petty Officer 3rd Class
Joined
Jan 1, 2011
Messages
95
Re: 1986 235hp Johnson strange bog down issue

Thanks Bob.
I dont think it was the cdi as it just sounded bogged down and not cough or spluttering. Im thinking if the compression was bad it would be like it all the time not intermittent,
I do believe the motor has been converted to having the oil injector removed so not sure what is involved in the fuel pump.
Although saying that, when i was 3/4 revs and it was going slow speed bogged down i tried squeezing the bulb a few times and made no difference.

What is involved in the carby overhaul?
Is it a basic thing like pulling off, strip down, clean parts put back and replace seals / gaskets in the process?

cheers.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1986 235hp Johnson strange bog down issue

You may want to double check the year. OMC did not make a 235 that year. Maybe it's the 175 engine-a detuned 235. Sounds like the engine ran normally after you had the one problem. If so, the fuel system is probably ok. More likely an ignition problem. Once warmed up, weak/older ignition components can to fail. (run fine when cold-crap out when warm.) You might want to take a timing light out next time you are boating. When the engine acts up, check each plugwire for firing with the timing light. That engine has dual power packs on it, one for each head. You can swap them for testing purposes.
 

stuee

Petty Officer 3rd Class
Joined
Jan 1, 2011
Messages
95
Re: 1986 235hp Johnson strange bog down issue

ok well i was looking into rebuilding the carbys and also the fuel pump along with and new impeller.
i cant seem to find sierra ones though the years seem a but out, im not sure if it because mine is an australian version.
This is my engine
1985 Johnson/Evinrude 235 - OMC, Johnson & Evinrude Parts Lookup
and the model is
J235TXCOR

if some of you great experts could tell me what kits i need i would appreciate it.
thanks
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: 1986 235hp Johnson strange bog down issue

When it acts up again, do a cylinder drop test on it to see if it's hitting on all the cylinders.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1986 235hp Johnson strange bog down issue

The factory (Bombardier) carb overhaul kit part number is: 439076. (you will need 3.) Bombardier does not make overhaul kits for the VRO pump, nor for the earlier dual fuel pumps found on the crossflow V6's up through 1983.
 

pn

Petty Officer 1st Class
Joined
Apr 20, 2013
Messages
374
Re: 1986 235hp Johnson strange bog down issue

i say sparkplugs.
 
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