1967 500 thunderbolt 50 hp power issue

[imand344]

I have a 1967 50 hp on a 14 foot 1962 dorsett- I cannot get over 12 mph- its a 40-50 mph boat- it runs great in the driveway on the muffs, once on the lake - she doesnt do anything but troll- The pee holes are steaming. Is it an impeller? If so are they difficult to replace>? and where do I find out how to go about replacing it? Im mechanically competent- But is this a bad idea for a first timer????

 

[andrewkafp]

Re: 1967 500 thunderbolt 50 hp power issue

Sounds like shes overheating. 40-50 knots out of a 50hp sounds a bit ambitious,I reckon about 35 max.<br />look here.<br /> http://www.myfishingpictures.com/showgallery.php?cat=500&stype=1&si=pump

 

[RICKRICK1]

Re: 1967 500 thunderbolt 50 hp power issue

DONOT run that motor any more as it sounds like you may have fried it (over heated). First and most important get a good manual and read it about your motor. You need to do a compression check, all cylinders with in 10% of each other and pressure should be above 95 psi. If compression checks out. Next replace the impellar. Again please do not run the motor untill you have checked it out.

 

[RICKRICK1]

Re: 1967 500 thunderbolt 50 hp power issue

oops double post

 

[imand344]

Re: 1967 500 thunderbolt 50 hp power issue

Thanks for the info Rick, I have ordered the whole impeller kit with the housing and all- <br />Ill let you know how the compression check turns out.