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need help on 80 merc

M

mr_shoes

New member
it starts up fine but when u give it gas it boggs n cuts out but starts right up i put new plugs in it new see threw fuel filter when the motor is off it fills up but when i start it there hardly no gas too been seen is that normal
 
Air is no problem in the filter unless it leaks.Check for water in the fuel.Clean the bowl on the carb.If it's dirty then a rebuild is necessary.Ethanol is messing up a lot of motors.It's delaminating the inside of older hoses causing clogs in the carbs and fuel filter.Check for soft hoses and junk in the filter on the motor.Check the diaphram. J
 
I have a early 70s Merc 80hp and troulbe shooting the fuel issue can be a real pain.Been there done that.To avoid doing things twice first check to see if your fuel tank vent is open,next make sure your fuel pick up inside the tank is not plugged.Make sure all fuel lines are in good shape.I put my bulb before my fuel filter (see thru kind) and it stays about half to 3/4 full while running.Check your bulb for air leaks,check your quick disconnect on your motor for air leaks.Not the best Idea but I bypassed that completly.Next check your fuel pump (diaphram may be defective).If you pump your bulb look at your carbs and see if they are leaking,if so time to rebuild the carbs.To save you some time and headache rebuild your carbs the right way take your time,the reason for saying this is because I thought I could get away with just blowing them out with some carb spray and air.Didnt work for me had to do it again.Once you have completed all this I would almost bet bottom Dollar your good to go again.Good luck and happy boating,,:)
 
short answer, if someone pumps the fuel bulb by hand and you bog down its not going to be the engine driven fuel pump since the manual pumper is hard at work. Most likely dirty carbs, you can try opening the mixture screw on each carb 1/4 turn but your only compensating for the crap thats already clogging the jets. Warning, no fuel through one carb mean no oil to the engine.
 
ok i put new fuel n tank new gas lines some sea foam in the gas mixed at 50 to 1 still the same boggs out when giving gas . what else should i look for
 
ok i think i found my problem a couple of wires in the external wire harness were falling apart so i repaired the wires now it starts up easy had it on the muffs put it in gear n ran just fine no bogg ill update tomarrow when i take it to the lake too see how she runs
 
ok did the carbs the carbs dident look too bad got it running n my buddie said the mix screw was off n that merc motors are funny if not set right well he set them right n ill be damn run good thanks too all
 
I still have a 64' Merc 800 that still pulls skiers and does everything I ask of it. It too had problems like you are having and after all the messing around with carbs, plugs, etc. it was the fault of a bad wire in the harness between the engine and the ignition switch. Caroded wire/s in more than one place. I use a olm meter to find the bad wire then started to cut open the harness to find it. There was more than one bad wire and bad in more than one location. The wires were caroded but not completely broken. They would allow some voltage to get through but not enaugh to provide current for heavy loads. The ignition circuit runs thru the harness.
You did mention you found a bad wire. You should check the harness for more bad wires. For what ever reason, there are several wires of different materials. Steel, brass/copper and none of them like moisture.
You may also have more than one issue. If it has points, assuming it is a 6 cyl, there are 2 sets of points, one set for every 3 cyl. These points are set with a degree meter and not by point gap. If they are not in sync, the engine will have poor power.
Good Luck
Bill
 
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