mercruiser 470 runs good.....for awhile :(

[DGIFF396]

My boats motor is plagued by the same problem as last year...its a 1978 470 and EVERY time i load it in the water it fires RIGHT up beautifully. Then I take it out and after a hour or so it loses power and wont go above 1500rpm. Did dons fuel test and its good? any advice....can a stator cause it

 

[ricksl1]

Re: mercruiser 470 runs good.....for awhile

been there done that,,,,had 470 woukd run all day in yard get it in the water , would get a mile or 2 -3 ..would start breaking up then eventally quit... check the coil... the 470 should have a restance wire to + side of around 9.5v in these oil filled/cooled coils tend to break down once they go bad...but while your there check /clean points (if you have a point system ),the other thing is the water cooled regulator..however these either work or they don't in most cases...this is lue of the fact that you have been completly trough the fuel system, the pick-up tube in the fuel tank should have a stainless screen filter on it and free of sediment ...one bad tank of gas can huant u later (sediment)....but going back, it really sounds like it could be the coil

 

[newbster]

Re: mercruiser 470 runs good.....for awhile

If you have not upgraded to the pertronics system then now sounds like a good time. It replaces the points and you bypass the resistor wire.