1973 Mercruiser 140 hp

[beericks]

Hey guys I got out on the lake today and what a nice day!!! I had one problem though...my boat would not get on plane. I can put it in neutral and get the engine to over 5000 rpm but once I put it into gear and full throttle I cannot get on plane and only go 7.5 mph max speed. Also the last 1/4 of the throttle will not make the boat go faster but only make it feel like it is loading up or something. Any ideas??

 

[Bondo]

Re: 1973 Mercruiser 140 hp

Ayuh,... Change the fuel filters...

 

[ziggy]

Re: 1973 Mercruiser 140 hp

revving the engine to 5k rpm under no load doesn't prove anything that i'm aware of..

imho, along with the fuel filters as a good place to start, i'd inspect for any or all of these items... http://forums.iboats.com/showthread.php?t=295070

 

[tgp***]

Re: 1973 Mercruiser 140 hp

Do I understand your question correctly??

When your in gear, the motor is motor still reving and your going nowhere??

if this is correct -- You may have a spun prop.

 

[beericks]

Re: 1973 Mercruiser 140 hp

Thanks ziggy and bondo...that is what I was thinking to start off with. No tgp I just dont have power WOT under load. I did have 5 gallons of old fuel(2 years old) but put in 10 gallons new along with my lead additive, stabil, and some heat (the gas cap was left off and I dunno if water got in there). I cruised around on the lake yesterday for 1 hour straight and could not get over 7.5 mph. Also if I punched the throttle it would just die. I would have to slowly increase throttle. Also could this be a float problem? How often should the fuel filters be replaced (my book says every year)? And how can I test if I have fixed the problem without driving to the lake?