gaining horse power

[wiskerchaser]

I currently have a 1979 70 hp johnson. Was curious if I could raise hp with engine rebuild? If so, does any one know how much hp gain is to be expected? Would it be more cost effective to sell and buy bigger? current motor has less than 300 hours.

 

[JB]

Re: gaining horse power

Howdy, WhiskerChaser.<br /><br />If your engine is in good tune you would gain nothing by rebuilding.<br /><br />Your engine is one of the great designs ever, but if you want more power the most cost effective way to get it is to get a bigger engine.<br /><br />Good luck.

 

[Solittle]

Re: gaining horse power

Before you jump out andd buy a bigger motor make sure that you are getting the max performance with what you've got. Often a good tune up, correct prop and engine hight will do wonders.

 

[wiskerchaser]

Re: gaining horse power

I got some help with the set up from Jehart. Smart feller, by the way.<br />Got the motor as high as possible and trimmed out as much as possible. I had a ventallating pro. "fixed know". I have a 15' shallow v with that 70 hp.just think it should be more agressive boat. The seventy horse just doesnt seem to kick it in the azz hard enough. any suggestions?

 

[dpg5]

Re: gaining horse power

there is no replacement for displacement. I have been chasing a hp issue and the solution is more motor.

 

[G DANE]

Re: gaining horse power

Just be aware, it you get a 85HP V4 or 115HP V4 you will jump to half of the gas mileage you got now - ready for that ?

 

[walleyehed]

Re: gaining horse power

Hmmmm...guess that means my 115 replacement, XP200(K), won't be a fuel miser...<br />NO sub for cubes....don't try and get more than the design will allow, it will cost you double in the long run.<br />BTW, with a properly running 70, that rig should skip along pretty good...What's the max rating??

 

[Chinewalker]

Re: gaining horse power

Hmmm,<br /> I've got a 75hp Johnny on my 15-footer and it kicks along quite nicely. How's the condition of the boat? I took 400 lbs. of saturated foam "flotation" out of my boat when I first bought it - made the difference between a slug and a slugger....<br />- Scott

 

[wiskerchaser]

Re: gaining horse power

The boat is in perfect shape, not as much as 5 scratches on hull. Perfect gell coat. The boat is a 1980 astroglass. Not so much woried aboat fuel consumption as i am over powering the boat.

 

[walleyehed]

Re: gaining horse power

Wisker, you still haven't said what the max rated hp is for your boat....It would be much easier to tell you what you should do if we know max rating...

 

[Dhadley]

Re: gaining horse power

Also, whats the motor turning at wot now?<br /><br />Rule of thumb -- if you can run the trim to the top and not vent the prop, its not high enough..........<br /><br />Good luck!