ok so i have a 35 hp mud buddy and i had been running it with a worn out prop for a while. id run it at 4250 rpms. i just put a new big blade on it last night. took it out today and i could only run 3620 rpm. motor is completley stock. there isa bit of a spuddering sound to the motor that i have never heard. sounds somewhat like an exauhst leak. has anyone ever had this problem or know what it could be? themotor has 90 hrs on it and is a surface drive. i also noticed today that on the cable that runs from battery to motor that the rubber has worn off somehow and it was sparking when i would turn because the wires would hit the metal on boat. if anyone can help me please do thank you cory carter. 918 869 2518

Sounds to me like you gots a brand-new prop that is now puttin' the bite in the water and now all you need is some good ole electrical tape to cover-up some naked wires .....

but it feels like i dont have much power?? 3620 rpms all i can get to. because the wires??

I ain't no-where near qualified to really be typin' 'bout the mechanics of the 35HP Briggs Vanguard engine ...... but it really sounds as if you doin' purdy good with that brand new propeller you just put the purchase on.

The naked wires ain't slowin' yore RPMs at all .... thays just jumpin' out of thays insulations.

What kind of speed are you acheavin' at 3650 RPMs ?

thats the thing man i am not going very fast at all. compared to how boat used to run. i used to run 25 i bet i was barley hitting 18 today. like there is nothing to do all its got is 3600 in it at the moment

Were you getting speed with your worn out prop at 4200?

If not, have a compression check done on your motor.

no not at alll man. with me in it just me it would run about like it did with a brand new one on it today. the motor acts like it bogs down a little but it takes off good after a second buth the speed is just not there. motor sounds weak to. im really hoping i havnt fried anything in the motor. prob going to be a pretty penny whatever it is. i will get that checked out though thanks bud

Compression test will tell you alot. If the compression is low, a leakdown test will tell where its leaking (intake valves are common). I had a leaking valve on one and it would surge between 7mph and 22mph under 3 man and hunting load. Valve job fixed it.

thanks for the info man'

the motor is getting wear on it. you have been running it for a while with a prop that has been getting smaller. the motor has not had to work to turn it. now that it has some wear on the motor you throw a new prop on it and it has to work its ass off to turn it.

some may disagree, but i beleave a motor will develop memory. maybe thats the wrong word, but it will wear different from another motor baised on how it was run, or how much work it was asked to do durring a given amount of time. take two motors. put them in a static load and run one at a low rpm and one at near red line. pull them down after the same hours and see how different parts have worn.

now i dont know the full history of the motor, but as posted he advised he has run a worn prop for a while. i feel i know what that means, wfo high rpm's trying to get from one place to another with a prop that isnt getting no traction. this means high rpm's and not enough prop to hold them down meaning not much load on the motor. this could damage or wear prats alone. you may not notice it with the old prop because the motor is not being asked for torque just rpm's. load it with a new prop now you are asking it for the torque and rpm's and it doesnt have them to give.

i just reread and see you posted big blade. this is probally more prop than the motor came with. that alone could account for the rpm drop.

MB 35's come with Big Blade 12.25x10P props

not always

Since '07 other than when they were out of props and sent out ones with the 3blade.

like i said, not always.

not to argue, but he posted he got a "new big blade". maybe im wrong, but that leeds me to beleave he had a small prop before. my thinkin if i had a bb prop before ide say " i just put a new prop on my boat" the fact that he said big blade makes me think its a different prop.

either way i bet the new prop is bigger than the one he just took off. saying he could turn a worn out prop 4250 and not be able to swing a new prop as fast, is right. that doesnt mean there is a problem.

I'm no expert, but I felt like arguing I would choose someone besides DB8 to argue with. Just saying.

we have a lot of sand here it has always had a big blade on it . props just dont last a long time. the motor just doesnt sound as mean as it used to. i am going to take it to a shop and get some test ran on it