increasing the horsepower

[72INVADER90HP]

I a 75 chrysler 90hp model 907hb 3 cly and I was wondering if there is any way to increase the horsepower by changing out the jets in the carbs with bigger jets? Thanks for any reply.

 

[The Marine Doctor]

Re: increasing the horsepower

To increase the hp this way you would have to increase the volume of air that is available to the cyl's as well. If you increase the jet size, you could possibly lose power.<br /><br />TMD

 

[72INVADER90HP]

Re: increasing the horsepower

Thanks for your reply. I was wondering but I guess I will stick to the 90 hp

 

[Spidybot]

Re: increasing the horsepower

In comparison with newer motors, keep in mind that the hp rating was different back in time.<br /><br />Then hp was given as measured at the flywheel - now it's on the prop shaft. This, plus whatever loss your motor may have suffered from wear and tear, would most likely make another '90hp' seem much more powerful.<br /><br />Even if your Chrysler purrs like a kitten, you should take great care if you invest in it's performance as it's value will not grow by the amount you invest.<br /><br />Sticking with it or replacing it sounds like the smartest decision.

 

[72INVADER90HP]

Re: increasing the horsepower

Thanks UU. My motor runs better than my uncles 88 suzuki and I would not get rid os it for anything. I was courious if there is any way to get more power.I have 148lb of compression on all 3 cly so I will not do anything to it.

 

[force01]

Re: increasing the horsepower

rob,<br />yes there things you can do to pump that motor up, but keep in mind if you raise the hp your dependablity goes down. bret<br /><br />If you need further assistance please email me @ forcepower01@yahoo.com.

 

[rbruce63]

Re: increasing the horsepower

Rob:<br /><br />I would invest in a full fledged tune up for this motor: Decarbonizing, checking the carburetors, checking the spark plug cables and ignition timing, etc.<br /><br />After this is done, I would connect a tachometer and measure RPM's at wide open throttle to check if the propeller is matched to your hull.<br /><br />If your propeller is turning at close 5500 RPM I would increase the pitch by a coulple of inches and this would in theory lower the RPM's at 4500 RPM. By increasing pitch at the recommended full ranghe RPM's you increase the speed of the boat and this will also reduce the wear of your vintage Chrysler and you will feel the motor is more powerful.<br /><br />I believe Chryslers were superb machines, but they are no longer produced and I have heard from others that their reliability was not on par with other top brands like Mercury or Evinrude. But, yours has demonstrated that at least it has outlasted many of the other brands.