1979 Mercury 175 turns over but intermittently start

[JC1979]

It started with the muffs off (no water) but does not want to start with the muffs. Some kind of pressure switch?

 

[Chris1956]

There is no pressure switch. Spray some 50::1 fuel mix into carbs, with flusher working and then choke and crank it.

 

[JC1979]

It started and ran great for half a day but then limped and sputtered back to the dock. It sounded like it was missing and intermittently had no power. Pushed throttle and nothing happened, but then 10 minutes later power was back, and then it died as I coasted into the dock. Maybe switch boxes or replace the fuel line?

 

[Faztbullet]

Wire to the idle stabilizer is questionable but I think is okay.

Get rid of this..not needed........

Pushed throttle and nothing happened, but then 10 minutes later power was back, and then it died as I coasted into the dock

Sound like stator dropping out......You sure stator was correct one??

 

[JC1979]

Not 100% sure on the stator but I did get it from an old-school local Mercury repair guy who looked up the serial number and seemed to know what he was talking about. I will call him to re-inquire.

 

[JC1979]

I definitely have the correct stator. Must be switch boxes or maybe fuel line? Or . . . I ran a moderate dose of seafoam engine/carb cleaner. Maybe a stronger dose?

 

[Faztbullet]

I ran a moderate dose of seafoam engine/carb cleaner. Maybe a stronger dose?

Never heard of Seafoam fixing electrical problems

 

[JC1979]

Right, just not sure if its an electrical problem or a fuel line problem. I guess I will check the spark and evaluate those switch boxes again.

 

[Dukedog]

Okay, so the starter cranks but it still doesn't start. I have replaced the stator, starter solenoid, some corroded wires, voltage recitfier, spark plugs, and battery. Fuel is fresh so presumably good. Spark tester shows a good spark. The trigger tested as good with the multimeter. I disassembled and reassembled the fuel pump. Fuel drips from carburetor when I back out the brass plugs so fuel is at least getting to the carb. I can't find any airflow restrictions but I don't really know how to verify. I have new switchboxes that I will install tomorrow. Wire to the idle stabilizer is questionable but I think is okay. I did get it to start and roar for a couple seconds today, but then it dies. It started and ran for 10 minutes on the lake a few weeks ago before I started "fixing" it. Any suggestions on where to go next? Fuel pump?

rebuild fuel pump with a "new kit".. clean/rebuild carbs using "all new gaskets".. check floats for saturation, reset... carb and pump gaskets/diaphrams don't like ta be used second time around no mater how "good" they look ..

 

[JC1979]

After switch box replacement it runs but seems to die at low RPM. Fuel problem or electrical? Looking at integrity of battery connections. Or just go ahead and rebuild the fuel pump, etc.? (Ordering fuel pump kit anyway.)

 

[JC1979]

Seems to die at low RPM.

 

[Faztbullet]

Will it stay running if you pump bulb? If so fuel pump weak,leaking check valve,air leak or low crankcase pressure