1987 mercury 45 hp (classic 50) bogging down

[yanta61]

i just got a 45 hp mercury and it starts and ideals great. once i put it in to gear and throttle up it starts to bog down.

i put in:
new spark plugs
new flue lines and primer bulb
2 carb kits and cleaned both carbs (were pretty clean to start with)
compression test
125# on all 4 cylinders

pulled the spark plugs and check to make sure they were all firing. have not done a spark plug test yet. just pulled the plug and held it against the motor to check it they were firing.

primer buld will prime up and stay primed. so both needles are seating in the carbs.

what should i look at next?????

Thanks
AY

 

[Sunfish12]

Re: 1987 mercury 45 hp (classic 50) bogging down

Did it bog before you rebuilt the carbs?

 

[yanta61]

Re: 1987 mercury 45 hp (classic 50) bogging down

yeah it was bogging down before i cleaned the carbs.

i did a spark test and had all 4 cylinders jumping 1/2"

 

[Sunfish12]

Re: 1987 mercury 45 hp (classic 50) bogging down

What rpm's does it bog at. You need to do an ignition compoment check as per the manual. Could possibly be the stator.

 

[yanta61]

Re: 1987 mercury 45 hp (classic 50) bogging down

i'm not sure what RPM because the guage is broke. i'm in the process of rebuilding the pontoon boat so maybe i can get the guage working. its about 1/2 throttle. i need to find a manuel for it

Thanks
Anthony

 

[MercNub]

Re: 1987 mercury 45 hp (classic 50) bogging down

I have the same engine and had the same problem last year. It turned out to be my powerpack. I rebuilt both carbs and rebuilt the fuel pump and bought a new fuel line pump, but nothing helped. If you have a inline spark tester you can connect it one at a time to verify there is spark. On mine cylinder 3 was dead and 4 was intermittent. Engine would idle and run up to about 2500 and then just bog. Could not get on plane and when I stopped the boat there was a mess of oil floating in the water around the engine . I replaced the power pack and now it runs great again. You should also check the rest of the electrical system also. Digital multimeters are cheap and I got a mercury shop manual on ebay for $20.00.

Hope this helps.