1977 55hp evinrude not reaching full power

[jordan04]

I have a 14ft. (fiber glass) bomber bass boat with a 1977 55hp evinrude. The boat has being going around 30 mph but, the past few times I have taken it out 25 mph is all it will do. The rpm was at 5200 going 30 mph but now the rpm is at 4600 or so.

What is causing this?

With this size motor should it be going faster??

Thanks guys.

 

[Wingedwheel]

Re: Enough Horse Power???

Re: Enough Horse Power???

When is the last time you re-built your carbs?

 

[jordan04]

Re: Enough Horse Power???

Re: Enough Horse Power???

about 2 months ago.

 

[steelespike]

Re: Enough Horse Power???

Re: Enough Horse Power???

See if it will respond if you tickle the choke.
Check that the carb(s) open all the way.
Is the bottom clean and smooth?

 

[jordan04]

Re: Enough Horse Power???

Re: Enough Horse Power???

yes if you close the chokes and open then fast it responds to that.

yes the carbs are opening all the way.

yes it is clean and smooth.

Thanks everyone.

 

[Bamaman1]

Re: Enough Horse Power???

Re: Enough Horse Power???

Check your fuel lines and gas tank to make sure there are no obstructions. Fuel filters also sometimes limit the available fuel. Also make sure your flame arrestor (like air cleaner) is clean.

 

[jordan04]

Re: 1977 55hp evinrude not reaching full power

ok checked all fuel lines and filters with no obstructions and the flame arrestor is clean.

This is puzzling me.

Any more ideas????

Thanks.

 

[Wingedwheel]

Re: 1977 55hp evinrude not reaching full power

Did you check the screens inside the carbs?

 

[Daviet]

Re: 1977 55hp evinrude not reaching full power

If you are sure it's a fuel problem, have you checked the high speed jets in the carbs.

 

[ronsealdeath]

Re: 1977 55hp evinrude not reaching full power

If you are sure it's a fuel problem, have you checked the high speed jets in the carbs.

I have a 55hp 1977 evinrude, pushes me and my mate at 31mph in our 14ft Shakespeare clubman. I would take off all fuel pipes and check then do a link and synch as per manual, check spark strength then if still no joy maybe you have a leak
I don't know what rpm mine does flat out as my tacho doesn't work but it sounds pretty flat out on a 15 prop if that makes sense. I rebuilt the fuel pump on mine, cheap thing to do and may help?