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| Prop blow out http://www.mudmotortalk.com/mmt_v2/viewtopic.php?f=2&t=1747 |
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| Author: | 1duckcrazy [ Sat Apr 25, 2009 8:07 pm ] |
| Post subject: | Prop blow out |
I need help from the experienced, I took my boat out for it's first run tonight with a mud motor and I could not get it to plane out with 2 people in the boat. I tried it with just me and it got on plane and seemed to run fine but I figure it would plane with 2 people also, any suggestions? With 2 people in the boat you could feel it grab and take off then it would blow out and fall back down. boat is a 16 ft home built johnboat style witha 23 Mud Buddy motor. Any advice or insite would be great. Thanks Gigafowl for gas tank suggestions it worked great now I just need to get this worked out and let the fun begin Thanks ,1duckcrazy |
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| Author: | Gigafowl [ Sat Apr 25, 2009 9:02 pm ] |
| Post subject: | Re: Prop blow out |
Don't have any answer for you - but what is boat weight and transom height - prop condition - rpm motor was turning on plane with just you versus rpm with load.... Strong suspicion regarding trim angle or height - or - prop wear could be culprit.... 23 hp should put over 1000 lbs of boat and gear on plane at 18 mph - if everything is right.... |
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| Author: | 1duckcrazy [ Sat Apr 25, 2009 9:51 pm ] |
| Post subject: | Re: Prop blow out |
Boat was running with me alone on plane about 3600 -3700 rpm I would say it was around 15 mph or so did not have my gps in today. Prop is a little rough on the leading edge but I have nothing to compare to as there are very few if any mud motors around here. I would say the boat is around 1000 with me in it maybe a little more. I built it with a 3/16" thick bottom for ice breaking and things that stick up in the Mississippi. it is a 16" transom height. Any ideas are helpful. Thanks again Giga the tank set up worked great! 1duckcrazy |
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| Author: | Gigafowl [ Sun Apr 26, 2009 6:55 am ] |
| Post subject: | Re: Prop blow out |
Lets talk about yer trim angle. I bet your motor was designed for 15" transom with a particular transom angle. On the trailer - trimmed down as far as it will go - where is the center of the prop shaft in relation to the bottom of the boat ? Prop - MB has used several prop mfg and designs - if you can remove it the pitch is likely stamped into the hub - you can measure the width - so on my 9x7 - it measures 9 inches across - has a 7 stamped into the hub - there is a huge difference in each pitch change too - 1000 rmp more on my 9x6 prop.... As a prop wears it looses overall width and width in the fat part of the blade too - 1/4 inch loss is dramatic on either measurement.... |
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| Author: | 1duckcrazy [ Sun Apr 26, 2009 6:44 pm ] |
| Post subject: | Re: Prop blow out |
Ok I looked at the relationship of my motor to boat and the center is same level as the bottom of the boat. The prop is 11" wide or a little less, the leading edge of the prop is beat up and rolled over some so I am pretty sure it is narrower on that width but nothing to compare to around here. I do suspect some is the prop but can it make that much difference? I have read on here about other guys changing there's and it makes a big difference. I am wondering now if I need a longer shaft on mine and should have gotten a different motor. Is there a way to lower them down? My transom is 15 1/2" tall Thanks 1duckcrazy |
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| Author: | Gigafowl [ Sun Apr 26, 2009 7:05 pm ] |
| Post subject: | Re: Prop blow out |
Trim angle sounds like the big issue.... You should be able to build a shim wedge - about 1/2" to 3/4" at the top narrowing down to 1/8" at the bottom.... You need that prop shaft to be capable of going down about 2 to 3 more inches.... Call the guys at MB - ask their advice - but I bet that will solve yer troubles - and won't cost much to impliment.... |
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| Author: | 1duckcrazy [ Sun Apr 26, 2009 7:30 pm ] |
| Post subject: | Re: Prop blow out |
I will call them tomorrow and see what they have to say. I will keep this in mind when I build my next boat but for now I just want to get it working correct to see if I want to get a bigger motor or not. Thanks for your help again, you have been very helpful 1duckcrazy |
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| Author: | deadbird8 [ Mon Apr 27, 2009 3:26 pm ] |
| Post subject: | Re: Prop blow out |
Any idea what the original prop width was? If that prop was a MB big blade, it started out 12.25x10. If its 11" now, thats alot of loss in performance. |
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| Author: | 1duckcrazy [ Mon Apr 27, 2009 5:16 pm ] |
| Post subject: | Re: Prop blow out |
I don't know what was stock on a 23 mud buddy light but if it is worn that much I am sure that is a big part of my problems beside the angle. If anyone knows let me know otherwise I am trying to get a hold of Mud buddy when I get a few minutes at work. Thanks for the input 1duckcrazy |
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| Author: | 1duckcrazy [ Mon Apr 27, 2009 7:55 pm ] |
| Post subject: | Re: Prop blow out |
Pulled prop off tonight and it is stamped 11/10 and it measures just under 11" so I have some wear. I will see what the prop doctor around here can do and see if that is some of my problem does any one know if this is stock for the 23 mud buddy lite? Thanks 1duckcrazy |
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