1974 650 thunderbolt 65hp need help lost wot power

[inx7979]

was out on lake today doing wot at 5000 rpms and suddenly lost plane and power but would idle fine but boat will not get up on plane now so took boat back home & checked plugs and found that all plugs had a little bit of oil on them so I assumed that maybe I fouled out a plug or two so I changed them all and again idles fine and sounds good out of water but this boat has been sitting for about 20 years & all I have done is changed impeller, fuel lines. battery cables,cleaned carbs,replaced throttle cables,fix choke switch & tlc so is there any thing I am missing like reeds , fuel pump etc... please help me out ! kids are dieing to do a hole day boating without breaking down

 

[petryshyn]

Re: 1974 650 thunderbolt 65hp need help lost wot power

If it idles fine, try helping the fuel system by firming up the primer bulb when it loses power. This could indicate a fuel starvation problem.
Sometimes these engines may have lost a cylinder from a bad pack and still idle well. Check for spark on all cylinders.

 

[inx7979]

Re: 1974 650 thunderbolt 65hp need help lost wot power

checked compression on all cylinders and is ok also had motor running and took off one plug wire at a time and each one I did I lost rpms so the next thing I was going to do is change the wires ,cap & rotor & rebuild feul pump but having a hard time to find parts so does anybody have any ideas