Hi everyone.
First boat for me.
I have a 1998 tidecraft wildfire with a 2s 1998 150 yamaha, it was sold to me with a 14x28p SS yamaha propeller. The engine would not get anywhere near the reccomended rpm range of 4500 to 5500. Wot run tests resulted in less than 4000 rpms. Looked at yamaha's website and could not find anything up to 300hp that reccomended a 28 pitch prop. So first stab at a replacement prop was a generic prop, alum 3 blade, at a 14x23pitch, and wow, its made so much difference, its like a new boat. With the new prop, 5000 rpms at full throttle. Middle of the reccomended rpm range for this engine. This generic prop is uncupped and probably not of the best quality of the props that are available.
But I noticed this and want some input if possible. With new prop had to hold back on throttle for first 10 minutes or rpms would go over 5500 max range. After the warming up, we could not get rpms over 5000 regardless of trim or throttle.
My question is: is this normal for a 2s engine? Or does the lowered rpm after warmup indicate the carbs may be to rich at WOT? Engine seems to run ok, What do you all think? Not asking for a fix, I just want some opinions on 2s engines and how they operate at wot. Relating to engine temperature.
Thanks for any opinions on this question.
Bill
First boat for me.
I have a 1998 tidecraft wildfire with a 2s 1998 150 yamaha, it was sold to me with a 14x28p SS yamaha propeller. The engine would not get anywhere near the reccomended rpm range of 4500 to 5500. Wot run tests resulted in less than 4000 rpms. Looked at yamaha's website and could not find anything up to 300hp that reccomended a 28 pitch prop. So first stab at a replacement prop was a generic prop, alum 3 blade, at a 14x23pitch, and wow, its made so much difference, its like a new boat. With the new prop, 5000 rpms at full throttle. Middle of the reccomended rpm range for this engine. This generic prop is uncupped and probably not of the best quality of the props that are available.
But I noticed this and want some input if possible. With new prop had to hold back on throttle for first 10 minutes or rpms would go over 5500 max range. After the warming up, we could not get rpms over 5000 regardless of trim or throttle.
My question is: is this normal for a 2s engine? Or does the lowered rpm after warmup indicate the carbs may be to rich at WOT? Engine seems to run ok, What do you all think? Not asking for a fix, I just want some opinions on 2s engines and how they operate at wot. Relating to engine temperature.
Thanks for any opinions on this question.
Bill