2 stroke question

quote:Originally posted by wolf

Or better yet write down all the data regarding rpm (wot),what it does in the water etc and take the prop to Don at west isle marine in sydney he will let you take out props to try and spend the time and find out what works for your boat he is a world of knowledge and been doing props for a very long time.

Good luck with your venture

Wolf
Good to know.... Thanks

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I finally got a chance to get the boat out on the water. Motor works just fine, It was nice and calm out on the water so it was the perfect day to get out. WOT the motor revs at 4900 rpm and you can hear that its screaming at that rev so I brought it down to 4500 rpms and everything felt smooth and ran great. 30 miles an hours fully loaded boat and 3 guys. There is nothing wrong with my motor or running it at the revs I am. You can hear that the motor likes it at 4500 rpms and anything higher is going to blow the motor up.... you can hear it!!! Thanks to everyone who helped me out with this.... I learned a lot about my motor, found I can run it at 4500 rpm... in fact it liked it and I picked up about another 10 miles an hour too. I'm not going to reprop.... no need too. Thanks again..... Steve.
Also picked up 2 hali's ... a 25 and a 15 pounder.... was a great day!!!

And remember....Keep your tip up!!!
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I finally got a chance to get the boat out on the water. Motor works just fine, It was nice and calm out on the water so it was the perfect day to get out. WOT the motor revs at 4900 rpm and you can hear that its screaming at that rev so I brought it down to 4500 rpms and everything felt smooth and ran great. 30 miles an hours fully loaded boat and 3 guys. There is nothing wrong with my motor or running it at the revs I am. You can hear that the motor likes it at 4500 rpms and anything higher is going to blow the motor up.... you can hear it!!! Thanks to everyone who helped me out with this.... I learned a lot about my motor, found I can run it at 4500 rpm... in fact it liked it and I picked up about another 10 miles an hour too. I'm not going to reprop.... no need too. Thanks again..... Steve.
Also picked up 2 hali's ... a 25 and a 15 pounder.... was a great day!!!

And remember....Keep your tip up!!!
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SeaRanger, I've been holding off replying here until I had some definite #s for you.

I've got an Arima SeaChaser 17, which is 200 lb lighter than your SeaRanger. 2000-115 v-4 2 stroke Johnson, running a Viper Stainless prop, 13 7/8 X 17 (3 blade). 3 guys, full gas/extra gas/full cooler :)/prawn gear/bucket of cannon balls in the cuddy/ WOT is 5400 rpm @ 38 mph. She sounds good at that rate, but an easy cruise is 4600 @ 32 mph give or take.

These boats are so light, 1250 lb for the hull, I can plane around 12 mph and would never have to "punch" it to get up. If I did, buddies and gear would be leaving over the transom.
 
SeaRanger, I've been holding off replying here until I had some definite #s for you.

I've got an Arima SeaChaser 17, which is 200 lb lighter than your SeaRanger. 2000-115 v-4 2 stroke Johnson, running a Viper Stainless prop, 13 7/8 X 17 (3 blade). 3 guys, full gas/extra gas/full cooler :)/prawn gear/bucket of cannon balls in the cuddy/ WOT is 5400 rpm @ 38 mph. She sounds good at that rate, but an easy cruise is 4600 @ 32 mph give or take.

These boats are so light, 1250 lb for the hull, I can plane around 12 mph and would never have to "punch" it to get up. If I did, buddies and gear would be leaving over the transom.
 
We tried bananas, I've never owned any outboard that turned less than 5000 rpms wide open when propped correctly. He will kill it in short order sadly. Probably will oval the wrist pins from lugging it to much.
 
Hey Ranger i just talked to Marc from Runabout as he is replacing my steering cable[V] He said you should be getting more rpm's but would have to see what's up.
 
Thanks Fins -n- Skins, I talked to your outboard mechanic and he shed a lot of light on this, In a nut shell he said if the motor is running fine at 4500 rpms that nothing is wrong as it is within the min rpm range however it will tend to lag on take off. He said this will not blow up the motor as long as there is nothing else wrong, in fact with keeping with the prop that is already on there that I will end up with more mph and less rpms. Where as if I was to switch the prop to a 15 pitch that would look after the rpm issue and get me out of the hole faster but I would be running at a higher rpm to achieve the same mph. He said if I did a lot of sking then I might want to change props but I don't ski. Stainless Steel is also a truer prop but is also damaged easier, I find it funny that I have talked to two different mechanics and they both say that if I can run on plane at 4500 rpms that there is nothing wrong with my outboard and yet some people on this site at hell bent on the fact that I am running the wrong prop. I know they mean well and thanks for that but their not mechanics. Thats one thing I've learned. I will try a 15 pitch prop to see which I like better.Thanks to all.... Steve.

And remember....Keep your tip up!!!
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I would like to thank all who had the patiants to educate me on the matching of a prop, motor and boat. Without you I would have never known the differaence in prop sizes. I have been listening and I will be trying out different props till I get my revs up a bit more. Thank-you.

And remember....Keep your tip up!!!
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You have not done an important test, verify your actual motor rpm as shown on the tach to the rpm the motor is actually doing.
It is very easily done and all the mech has to do is to hook up a timing light and if he is any kind of mechanic he will have a timing light with a tach on it and other important info on it.
You absolutely should not trust your tach unless it has been checked in such a manner.
YOUR MECHANIC IS NOT CORRECT WHEN HE SAYS THAT A s/s PROP IS EASIER TO BREAK, IT IS THE WEAKER PARTS THAT BREAK SUCH AS PROP SHAFTS GEARS,ETC. An aluminum prop will break first and should be used in situations where there is much debris in the water.
Listen or not at least verify your tach is working right.[^]

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quote:Stainless Steel is also a truer prop but is also damaged easier

HUH???? a alum will dent alot faster a SS hardlly ever gets damaged.

Good luck Wolf
 
quote:Originally posted by Gunsmith

You have not done an important test, verify your actual motor rpm as shown on the tach to the rpm the motor is actually doing.
It is very easily done and all the mech has to do is to hook up a timing light and if he is any kind of mechanic he will have a timing light with a tach on it and other important info on it.
You absolutely should not trust your tach unless it has been checked in such a manner.
YOUR MECHANIC IS NOT CORRECT WHEN HE SAYS THAT A s/s PROP IS EASIER TO BREAK, IT IS THE WEAKER PARTS THAT BREAK SUCH AS PROP SHAFTS GEARS,ETC. An aluminum prop will break first and should be used in situations where there is much debris in the water.
Listen or not at least verify your tach is working right.[^]

IMG_1445.jpg

Now theres some solid advice! Good job gunsmith.

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Fill the dam tub!
 
I've owned boats since 13 years old (I'm 50 now) and do my own mechanical work, including complete tear downs and rebuilds. It is more preferable to have your engine achieve the higher end of the manufacturers recommended rpms than the lower end. The result will be less wear and tear and longer engine life when operated at normal cruise speeds.
 
Me thinks your wasting your time Rollie, totally agree with you!!! on my outboard I spent almost a whole day and tried 8 different props to see which gave me my max rpm/speed/and out of hole tests and recorded it all and then took all my findings to a well known prop guy and he suggested which was best and went with what we both agreed upon.


Wolf
 
quote:Originally posted by profisher

I've owned boats since 13 years old (I'm 50 now) and do my own mechanical work, including complete tear downs and rebuilds. It is more preferable to have your engine achieve the higher end of the manufacturers recommended rpms than the lower end. The result will be less wear and tear and longer engine life when operated at normal cruise speeds.
Thanks Pro, its good to know that, in fact that was a question I had.

And remember....Keep your tip up!!!
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quote:Originally posted by wolf

Me thinks your wasting your time Rollie,


Wolf
Wolf, I'm sorry you think this is a waste of time. Lucky for me there are people on here who will take the time to help someone who has never had a prop problem before.

And remember....Keep your tip up!!!
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quote:Originally posted by Gunsmith

You have not done an important test, verify your actual motor rpm as shown on the tach to the rpm the motor is actually doing.
It is very easily done and all the mech has to do is to hook up a timing light and if he is any kind of mechanic he will have a timing light with a tach on it and other important info on it.
You absolutely should not trust your tach unless it has been checked in such a manner.
YOUR MECHANIC IS NOT CORRECT WHEN HE SAYS THAT A s/s PROP IS EASIER TO BREAK, IT IS THE WEAKER PARTS THAT BREAK SUCH AS PROP SHAFTS GEARS,ETC. An aluminum prop will break first and should be used in situations where there is much debris in the water.
Listen or not at least verify your tach is working right.[^]

IMG_1445.jpg
I will get this done.... thanks.


And remember....Keep your tip up!!!
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