1975 115hp surging and loss of power

[firstboat25]

Hey Guys

Well I took my boat out today and had a terriable trip
When I would put her in gear she would be fine but as I increased the throttle to pick speed after about 10 or 15 seconds at mid throttle or at full throttle she would be going along fine and then lose everything then pick up and go again and then lose everything etc. If I go from neutral to full throttle she takes right off but then she loses power and comes back etc.
Any ideas what is causing this and how can I fix this ?

 

[iwombat]

Re: 1975 115hp surging and loss of power

A little better description of "lose everything" would probably help a bit.

 

[jtexas]

Re: 1975 115hp surging and loss of power

Fresh fuel?
Fuel line holding pressure?
Fuel tank vented?
Fuel filter clean?

If pumping the primer bulb when she loses it causes her to regain power, rebuild the fuel pump.

Do a compression test.
And spark test to rule out faulty ignition. Spark should jump a 1/2" gap.

If that's all good, suspect clogged carbs.

 

[firstboat25]

Re: 1975 115hp surging and loss of power

A little better description of "lose everything" would probably help a bit.

Sorry about that I mean that she loses all her power then regains it and loses it again

 

[firstboat25]

Re: 1975 115hp surging and loss of power

I had just filled her up with fresh fuel that morning and the fuel tank is vented I will have to check the fuel lines though and I will also check the fuel filter
Im thinking carbs also

 

[imported_lorin]

Re: 1975 115hp surging and loss of power

Surging often indicates an air-intake leak.