Thermostat housing hole.

Faztbullet

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Mar 2, 2008
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13,998
You definitely need to repair/replace the prop as it will cause too much loss of thrust. RPM will be high and speed low and both readings will be incorrect.
 

Sea Rider

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Doug, post a pic of current prop to show how much is damaged. Some issues : As current prop has not been tached before when was brand new won't know if going for new exact same diam/pitch or to a lower pitched one. Repairing current one at a prop shop will surely cost as much as half the price of a new one just to tach it right and then probably need going for a new less pitch prop if wanting the motor to run towards its max wot rpm range to achieve a fantastic hole shot and excellent top end speed.

Personally would test current prop as usually loaded on a wot run on flat calm water cond and check the max rpm achieved, but need to have current tach well set to read true wot rpm and go straight for a new OEM prop.

Happy Boating
 

Sea Rider

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Who's prop is the one shown in post 263 ? For just $40 which it's near half the price of a non OEM new prop will be money wise to spend and check the max wot rpm achieved as usually loaded hopping that dials at least 5500 wot rpm.

Happy Boating
 

Douglasdzaster

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Who's prop is the one shown in post 263 ? For just $40 which it's near half the price of a non OEM new prop will be money wise to spend and check the max wot rpm achieved as usually loaded hopping that dials at least 5500 wot rpm.

Happy Boating
It’s mine. Fastbullet must have used one of my previous pictures. It looks a little different now. I’ll post a picture.I’m not sure this wasn’t a spare. There’s another stainless prop needing a hub and has a fracture that was in the boat when I bought it. Definitely not OEM. I can’t tell who the manufacturer was.The aluminum that’s on it now is around 11” and the stainless is 10”. It’s going to be a while before I run it. This time of year the wind is always blowing. May get a calm day every now and then. In the summer it’ll calm down. I have to stop running wot all the time in the rough water. This boat wasn’t made for it.
 
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Douglasdzaster

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The leading edges are burred...you can have the prop touched up/trued for around $40


View attachment 339262
I’ll post a better picture of it. My last time out it was real windy and I beat up everything I think. I keep acting like I’m back in a bass boat and this old boat can’t take it. I have a stress crack in the transom now. I’ll have to get it welded. The prop doesn’t look as good as this picture now. Let me know what you think when you see the new pictures. I appreciate it.
 

Sea Rider

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That's why its imperative to test the combo on flat calm no wind water condition whenever possible, will assure runing the motor at it's max throttle grip on a flat water surface, then going next for a prop maximization for motor to run at its max wot rpm factory stated.

Why should you go that way :
-The combo will achieve a fantastic hole shot and nice top end speed.
-Once on plane can maintain the combo on plane at reduced throttle.
-Will reduce the motor's fuel comsumption while cruising saving some cash for the cold ones.

With respect to current mentioned 9 and 10 props, will you send them to a prop shop and have them fully repaired and test both latter at wot and stay with the one that achieved the highest wot rpm towards max.

BTW, If FB has given already his tech veredict, that prop is shot and no good to wot test like this...

Happy Boating
 

Douglasdzaster

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Sep 11, 2020
Messages
185
That's why its imperative to test the combo on flat calm no wind water condition whenever possible, will assure runing the motor at it's max throttle grip on a flat water surface, then going next for a prop maximization for motor to run at its max wot rpm factory stated.

Why should you go that way :
-The combo will achieve a fantastic hole shot and nice top end speed.
-Once on plane can maintain the combo on plane at reduced throttle.
-Will reduce the motor's fuel comsumption while cruising saving some cash for the cold ones.

With respect to current mentioned 9 and 10 props, will you send them to a prop shop and have them fully repaired and test both latter at wot and stay with the one that achieved the highest wot rpm towards max.

BTW, If FB has given already his tech veredict, that prop is shot and no good to wot test like this...

Happy Boating
Here’s the worst of the three blades. I’m thinking it maybe getting kind of thin. The prop shop said for the stainless it will start at $100 for the hub and it needs a fracture fixed and other work. I don’t know what kind of prop it is or if it’s worth much. The only thing I find on it is Lochridge stamped on one side and the other side is ...M70 21p. The 21 has an x stamped over it then a 14 stamped under it. That’s a big change in pitch isn it? I can make sure it’s at least right diameter where hub goes. Then send it with a cc# then they’ll let me know something. Most it’ll cost me is freight if it’s not going to work out. Can’t find any numbers on the aluminum anyway so I still wouldn’t know where to go with pitch.
 

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Douglasdzaster

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Here’s the worst of the three blades. I’m thinking it maybe getting kind of thin. The prop shop said for the stainless it will start at $100 for the hub and it needs a fracture fixed and other work. I don’t know what kind of prop it is or if it’s worth much. The only thing I find on it is Lochridge stamped on one side and the other side is ...M70 21p. The 21 has an x stamped over it then a 14 stamped under it. That’s a big change in pitch isn it? I can make sure it’s at least right diameter where hub goes. Then send it with a cc# then they’ll let me know something. Most it’ll cost me is freight if it’s not going to work out. Can’t find any numbers on the aluminum anyway so I still wouldn’t know where to go with pitch.
I just found a web site that I could enter my motor, type of boat , size, and weight. And got an estimated size of 11”x 17” pitch.
 

Sea Rider

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I just found a web site that I could enter my motor, type of boat , size, and weight. And got an estimated size of 11”x 17” pitch.
Check if Yamaha has a Prop Selector Page, if so, fill in the required data and check which prop diam/pitch calls for your application.. See if matches the previous recommended one.

Happy Boating
 

Douglasdzaster

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Messages
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Check if Yamaha has a Prop Selector Page, if so, fill in the required data and check which prop diam/pitch calls for your application.. See if matches the previous recommended one.

Happy Boating
I just found the perfect solution. I just got off the phone with a guy that sells props. He said to bring my boat and I can go to a near by lake and test run them to select the proper size. Then order the one I need or he’ll sell me a used one if I want. I’m going to get two with different pitch sizes. The spare will be for when I have a load. Now I got to get the other work done to the trailer etc. so I can do that. Before I found the fuel leak I messed with the cdi adjustment so to get it right I may have to do a link and sync which I didn’t do anyway when I reinstalled the carburetors. I still haven’t been able to move My boat back here to the water source. They have one more load to haul off (hopefully today) then I can have my driveway back.
 

Sea Rider

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Make sure the tach reads true rpm, useless going for new or used props blindly, that way won't get the max HP cowl rated any time soon...

Happy Boating
 

Douglasdzaster

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Make sure the tach reads true rpm, useless going for new or used props blindly, that way won't get the max HP cowl rated any time soon...

Happy Boating
Yes sir, I’m not going to do it until I get the tach set right. I’m going to run it here tomorrow and make sure it reads idle correctly then when I can take it and run on the lake to check wot. I’ll be reporting in. Also the prop guy said he’s gotten pretty good at looking at a rig and taking measurements and getting the right prop. I told him we’ll see when I go test run the ones he gives me to try out. Oh and Yamaha recommended the same prop on their web site.
 

Sea Rider

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Yes sir, I’m not going to do it until I get the tach set right. The prop guy said he’s gotten pretty good at looking at a rig and taking measurements and getting the right prop.
Getting the right prop by simple looking along measuring a rig it's just a reference as deck load, worse if variable has not been taken into the least consideration and will knock down that equation. Will also depend entirely if (1) wanting a fantastic hole shot with slight less top end speed or (2) a slower hole shot with slight top end speed increase, that scenario will be accomplished when running middle to max wot rpm range factory stated and those ranges varies from motor manufacturer to manufacturer. Something positive in your favor is that you're running a near fixed load which is good and entirely up to you if going for any of both 1-2 propping alternatives.

For me (1) on all my boats running maximized OEM props and a fixed load. A tachometer will knock out anyone who claims to have the best musician ear when it comes to wild guessing at which high wot rpm the motor is running at, that's what tachs are for. Hey Doug, at 6 K visits better change the title of the thread, we have been troubleshooting the whole motor, boat and trailer...LOL!!

Happy Boating
 
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