Honda 75 engine

U

UncleRichie

New member
Hi,
I have a 75 horse carb honda on my 22 cruiser and am happy with the way it runs I have the prop recomended for it top speed of 32 miles per . I bought a spare from honda that is a little more then it likes . My question is top rpm is about 54 to 55hundred witch is where it should be but when working on it I found that the carb throtle does not go all the way open ( when the throtle lever is pushed all the way ) I took the housing off one day while on the water and hooked a string to the throtle just to see what the differance is the engine will turn way more then it is supposed to ,I also tried the larger prop and could still get it way past red line ( stopped before then) has any one else noticed this? If I could use this extra throtle I could use a lot more prop . With the larger prop I was way south of 36 miles per and still pulling strong but was at max rpms. Has anyone else noticed this or is this hondas way of making shure we don't destroy the engine?
Richard
 
Hi Richard, I dont have a clue, but I hope you get some good answers because they would certainly help me too. Why I replied is I just bought two new props, one stainless and one aluminum 15P and I am not sure how my 22 cruiser is supposed to perform. I wanted to know what prop you are using. I am not getting RPMs over 5000 and speeds of about 25.
John
 
UncleRichie":3pyjyp99 said:
Hi,
I have a 75 horse carb honda on my 22 cruiser and am happy with the way it runs I have the prop recomended for it top speed of 32 miles per . I bought a spare from honda that is a little more then it likes . My question is top rpm is about 54 to 55hundred witch is where it should be but when working on it I found that the carb throtle does not go all the way open ( when the throtle lever is pushed all the way ) I took the housing off one day while on the water and hooked a string to the throtle just to see what the differance is the engine will turn way more then it is supposed to ,I also tried the larger prop and could still get it way past red line ( stopped before then) has any one else noticed this? If I could use this extra throtle I could use a lot more prop . With the larger prop I was way south of 36 miles per and still pulling strong but was at max rpms. Has anyone else noticed this or is this hondas way of making shure we don't destroy the engine?
Richard
Click to expand...

Hi,

The answer is "it depends". The throttle cam on the Honda BF75 has an index mark that the cam follower aligns with at idle. If the person that set the throttle cable didn't align that properly (i.e. - set the cable with the throttle cam follower at the bottom of the slot) you won't get full power. When set right there is some open space at the top of the cam slot when at wide open.

The Honda BF75 has a wide open throttle range of 5000 to 6000 rpm. The engines seem to run best if they're propped for the upper half of that (5500 to 6000 rpm) and max horsepower comes at 5500 rpm.

If you're using a Honda aluminum prop the choice would typically be the 58130-ZW1-015AH which is a 3 bladed 15" prop.

Top speed is typically just at or just below 30 knots, on a light boat it could be a bit higher but not by much.

Les
 
I've never cruised with a "light boat". I'm always fighting weight in my boat. I want to take everything I own! Heavily loaded I cruise at about 23 - 26 mph. The Gulf seems like it is always choppy so this is a good speed for me.
 
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