Chrysler 115HP - Estimated Speed

dan1979

Seaman
Joined
Jun 16, 2008
Messages
54
I just got a new (old) motor, its a 1980 Chrysler 115HP. I have it on my 16ft fiberglass v-hull boat. I am just curious as to what speed range I should expect before I take it out for a test run.

Thanks,
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: Chrysler 115HP - Estimated Speed

Everybody always estimates their speed as "about 40" Guy has a 75 on a 22 foot cuddy ask him how fast it goes, and he will tell you "about 40"

I have a 90 on a 15 foot Glastron deep vee. It reaches about 40. LOL actually, between 42 and 45 depending upon its mood. That's with me alone in the boat and 2 six gallon tanks at the back.

I would expect about the same with a 115 on your 16 ----BUT-----Every hull is different and will get a different top speed from the same engine.

Also, propping is critical. The incorrect prop will lose you 5-8 MPH. I suspect a nice 13 X 19 pitch prop would work well as a starting point. But: it depends on the condition of your engine. Compression a little low and she may not swing that much prop. --LOTS OF VARIABLES--you may want to play a bit.
 

dan1979

Seaman
Joined
Jun 16, 2008
Messages
54
Re: Chrysler 115HP - Estimated Speed

Frank,

Hey thanks for the reply. And yes, you are correct.. "About 40" is what I always hear. haha. If I get 40 mph I will be more than happy. My hull is in good shape, the boat is basically same style as a 16' Bayliner.

The engine seems very strong, I have replaced a lot gaskets, fluids, cleaned carbs, etc..., But, I haven't had it in the lake for a real test. She can purr all she wants on land. :D

I have yet to check the compression though, do I need a special tool to do this?
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: Chrysler 115HP - Estimated Speed

Compression testing hose and gauge---about 20 bucks in the auto stores. Screws right into spark plug hole.

Brand new, readings were up around 140 PSI. (125-145) If you get 120-125, you will probably be doing OK. BUT: Quality of gauges varies so your readings may not be actual and may be low. The important thing is that all cylinders be within 10 pounds of each other. Trouble is when you get 120, 120 125, 50. Then you know one piston has issues.

I noticed your locale is Colorado. I forgot to mention in the last post: If you are boating around Mile High City, then be sure the engine carburetors are properly jetted for altitude. And if you are at altitude, the engine will produce less horsepower, usually swinging less pitch on the prop, thus, less speed
 

dan1979

Seaman
Joined
Jun 16, 2008
Messages
54
Re: Chrysler 115HP - Estimated Speed

Frank,

Thanks for the info on getting a compression checker. I am located in Denver, and the majority I go to lakes that are around 5500 - 8000 ft. How do I determine, or, get the carbs properly jetted for altitude. (new to adjusting carbs)

Thanks,
 
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