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engine bogs down in high throtle


Petrie's Avatar
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07-14-11, 08:59 AM   #1  
engine bogs down in high throtle

my 6.5 hp Johnson Belgin Model CJ7RST Serial 87401720 Starts easily but when I reve it to high speed it would bog down and stop.
I removed the Carb cleaned it reinstaled it ran fine in nuteral but as soon as I put it in gear and reved it up the the engine bogs down Just as before
If there is any idea what could be the problum I would Appricate hearing them

Petrie

 
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07-20-11, 11:01 AM   #2  
I don't know how old your motor is but it sounds like it could be an ignition problem, meaning you have one cylinder not firing and the other one of course reving in neutral, but under load it bogs down with insufficient power. If it is an old school motor I would suspect it needs a new magneto for example. Did you check for spark from both plugs. If not, pull one wire off at a time when it is running and you will easily know what is or is not going on then.

 
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07-20-11, 04:23 PM   #3  
Did you take the carb apart and clean it? Did you install any new parts when you had it apart? Has this just started happening or did you just buy the engine?
Is the proper prop on the engine? Are you running it in water or on a test setup?
It could be it only needs adjusted for high throttle. Maybe the throttle linkage is loose.

 
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07-23-11, 04:22 PM   #4  
The problum started after I serviced it last fall it had a cracked carb cover the Johnson dealer had trouble find this model # told thatthe psrt was no longer available an it was suppered by part # 436316 since cleaning the carb and installing the new cover this proublum has existed I am wondering if this the proper cover
I checked the spark it is running on both cylinders and compression is 100 PSI in both
since I posted this problum Icleaned the carb again now when I start the engine when I reveit up in nutrel ittakes the gas but as soon as i return it to idle it stopes and it is hard to start
I am running it in a test tank
Petrie

 
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07-23-11, 06:51 PM   #5  
Does that engine have both a high speed and low speed mixture screw? Perhaps your low speed is leaned off too much and needs to be backed off a little. Just another thought in a list of possibilities.

 
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08-03-11, 02:06 PM   #6  
It seams the trouble with the engine is that it was made in belgian an the nodel # dosent show up so the parts dont seam to be available

Thanks for all your support
Petrie

 
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08-04-11, 09:18 AM   #7  
Is there any way you could do some kind of a repair attempt on the old cracked cover using something like JB Weld for instance?

 
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08-28-11, 04:27 PM   #8  
Sorry it took me so long to replay to all of you that offdered me your advise
the problum was the air box
after three young mechaicks couldnt find the problum there boss called me to see if I could find the problum
After I repaired it last fall it ran well until this sumer then it was brought in for servicing in the summer
after asking yor your assistance and folowing all of your suggestions
AS a Last trial I held my fingers over the carburator intake the motor started running fairly normal
As I was doing this I sprayed some brake cleaner along the caruburater the engine satrted to bog down I let more air into the intake by removing 1 finger it reved right back up There was 2 bolt holes with no bolts
The young mechanic said I found a air box in the shop does it belong on that engine I checked the air box and where the 2 bolts that were missing were in the air box
I installed the air box presto game over
Engine runs fine

thank all of you
Petrie

 
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