do outboards lose HP as they get older?

[JesseBannor]

I have an older 18' Sea Star with a 130hp Chrylser Outboard on it. My friend that owned it before is a mechanic and the engine is clean and in great shape. When I take the boat out though, I can only get it to go 25-30mph with only two people on it. That seems slow for an engine that size. The prop is a little bent up and i know a new one would help a litte bit, but shouldn't I see more speed? How do I get my boat to go faster? I can't afford the $7,000 plus for a new 130hp motor, any suggestions? Thanks all

 

[CATransplant]

Re: do outboards lose HP as they get older?

Well, that could be a lot of things. Odds are that your motor is not running as well as it should. A complete tune-up should correct that, but you need to check the engine's compression on all cylinders as part of that tune up. If the compression is under 100 or one or more cylinders have compression over 10% lower than the rest, there may be more work involved than a simple tune up.<br /><br />Your bent prop is a big problem. Get it repaired or get a new one. That's a must.<br /><br />Also, how's your boat? Is it waterlogged? Many old boats are, and that will most definitely slow things down a good deal.<br /><br />Do you have a tachometer on your boat? If so, what RPMs is it showing when you're running with wide-open throttle (WOT)? That information can help us know if your outboard is running properly.

 

[JB]

Re: do outboards lose HP as they get older?

What CAT said.<br /><br />An outboard that is in good condition and tune probably makes more hp due to well broken in friction and bearing surfaces than it made new.

 

[bluewater19]

Re: do outboards lose HP as they get older?

When I first got my starcraft from my buddy I would only go 33 mph on the GPS. It had a bent/dinged prop and no tune up for 2 seasons.<br />I replaced the prop with the same pitch/brand and tuned the boat up. It will now do 39 mph on the gps. A clean prop and good tune may be all you need.

 

[umblecumbuz]

Re: do outboards lose HP as they get older?

Outboards are like you and me.<br /><br />We grow up and peak, then we slow down and die. Some of us peak later and longer than others, but the end result is always the same.<br /><br />I haven't yet found an outboard that holds its peak indefinitely, or that doesn't eventually die.<br /><br />Sad, ennit?

 

[Triton II]

Re: do outboards lose HP as they get older?

And it's cumulative. The cylinders wear. The pistons wear. The gears in the driveline wear. They wear in, and everything gets comfortable together. Then they wear out and things start to slow down. A worn out prop doesn't help, nor does sludgey lower leg oil, sooted up exhausts and combustion chambers etc.