1970 Evinrude wont run at wot

[pecheux]

Good day y'awl. (lol) I am responsible for getting my son's 6 hp up and running every spring. This year as usual changed LU oil and ran the motor in garbage can to make sure water pump runs good and ajust carburator for idling low speed. All went well until I installed the motor on the boat for a test run on lake. Motor kept on idling well but would not accelerate to full power. Let's say it got half way there and once in a while power would pick up and give a burst only to get back to half speed.
Plugs are new, + fresh gas/oil mix. Can condensation water in carb bowl cause this kind of problem ? I thought electric problem but then why would it run so good at idle and misfire upon cranking up the trottle ? Thanks for you opinions.

 

[BonairII]

Re: 1970 Evinrude wont run at wot

Check for good spark. Is fuel tank vent open? Does choking it help at all?

 

[pecheux]

Re: 1970 Evinrude wont run at wot

fuel tank vent was open, choking killed the engine, (while trottle handle is at wot position) spark is good enough for nice steady idle. Dont know how to check this at wot. Tx for your feedback.

 

[BonairII]

Re: 1970 Evinrude wont run at wot

Have you cleaned carb lately? Was the fuel emptied or has fuel sat in bowl all winter?

 

[boobie]

Re: 1970 Evinrude wont run at wot

Do a cyl drop test on it to see if it's running on both cyls.