motor bogging down?

[Becauseican]

i have a 85 40hp johnson that would die in the water but ran fine on the hose. took it to shop and they cleaned carbs. it ran a little better but would still die so i took it back.they put a new diiaphram in full pump. Now it takes off and bogs down then picks up and repeats several time then stays bogged down. it keeps running but stays bogged down. trash still in carb? bad gas? sucking air in full line? any suggestions before i take it back to shop?

 

[Daviet]

Re: motor bogging down?

Could be a fuel problem, fuel pressure, clogged high speed jet, needle and seat in carb stuck not letting enough fuel into carb.
Could also be dropping a cylinder, loosing spark on one cylinder.
Try pumping the primer bulb when it acts up, this will bypass the fuel pump, if pumping the bulb does not help, your problem is probably in a carb or ign system.
You could also try squirting some fuel mixture directly into the carbs when it acts up, if it picks up and runs properly, your ign system is ok and you have found out which carb is giving you problems.
You should also post your model number so we know exactly wht engine you are working on.

 

[Becauseican]

Re: motor bogging down?

i will check those things when son gets home. i am going to put it in a small pound i have because i keep having to drive an hour everytime i need to work on it..i hope it doesnt tear something running it on the trailer in the water. i have been mixing the gas/oil 50/1. is that correct? if mixture is to thick not only would it bog down but would smoke like a chimmney correct?

 

[Daviet]

Re: motor bogging down?

50:1 is correct mixture.
You can run the engine with the lower unit in a trash can or large tub, just make sure the water level is well above the water pump, and be careful to keep the water level up as water will spalish out when the engine is running.

 

[Becauseican]

Re: motor bogging down?

i have tried with trash can and it runs fine.same as when on hose but as soon as i put it in the lake it dont work.i guess there is more pressure in the lake than in trash can.

 

[Daviet]

Re: motor bogging down?

My mistake, you can't run the engine under load at high speed in a barrel, needs to be in the water.

 

[Becauseican]

Re: motor bogging down?

it should be ok on trailer if not giving more than half thottle you think?

 

[Daviet]

Re: motor bogging down?

You can run it wide open on the trailer as long as it is in gear and the prop woun't hit anything. You should not have any problems with 1/2 throttle.

 

[Becauseican]

Re: motor bogging down?

Ok, i replaced the gas started motor up and still bogged down. i pumped bulb while running with no change. i sprayed gas in carbs and the top carb was no change but the bottom would rev engine up more so i'm going to take it off and attempt to clean it again. when i took it off before i could not get the needle walve out. if i still cant get it out will it be ok to take check valve and the rubber washers and the float out and soak the carb in some carb soaker i got from auto zone or is there something else in the carb that the chemicals with eat up?

 

[Daviet]

Re: motor bogging down?

It sounds like you might have a high speed jet clogged. You might be able to clean it while it is on the engine. You didn't post a model number, but this should be close.http://www.ishopmarine.com/ishop/js...CatFilter=BRP&eCatSupFldr=supplier-100-005-EJ
Remove # 12 or 28, whichever you have, the high speed jet (#19) is behind it. It takes a special sized screwdriver to remove it, but you can use a piece of SOFT copper wire and try and clean it out, of course the best way is to remove the jet but sometimes you have to do what you have to do.

 

[Becauseican]

Re: motor bogging down?

model # J40ELCO that was not my carb because my jet (i think its the jet) screws up from the bottom of the carb not where the drain is.

 

[Becauseican]

Re: motor bogging down?

will it be safe to soak the carb with the float and check valve and its washers out? if thats all i can remove.

 

[Daviet]

Re: motor bogging down?

I have looked at every model 40hp made in 1985 and cannot find one that the jet screws up from the bottom.
What is your model number so that we can look at your exact carb.

 

[Becauseican]

Re: motor bogging down?

you was right about the carb diagram..my mistake..sorry..anyhow the carbs have been cleaned 3 times. new fiel pump diaphram. still the same results. can idle around in water at about wake speed but anymore fuel and bogs up and down then stays bogged dowm. i recall reading on this sight before that someone having this problem and it turned out being an electrical problem.is there a wway to test any of this with out high-tec testers? also if the air flow is not set exacly correct will it couse this or would it just cause it to run rough?

 

[Becauseican]

Re: motor bogging down?

model # again is J40ELCO

 

[Becauseican]

Re: motor bogging down?

I have been studying that diagram from earlier in this post and i dont think i have that #7 washer in my carb...looking at the diagram it looks like in goes over that long jet comming out the bottom of carb that goes down into the bowl where the high speed jet is at...is this correct?

 

[Becauseican]

Re: motor bogging down?

Thanks for the help!!!!! i found the problem. was the gasket #7. was missing on both carbs. once again THANKS

 

[Daviet]

Re: motor bogging down?

See, ask questions and someone will help you out.
Glad you found your problem.