I have a 1986 Volvo penta 280 outdrive. at low speeds it is fine but when I accelerate it jumps out of gear. I have taken it to the rebuilders twice, what could be the problem?
Welcome to forum,check your shifter mechanism behind back cover ,make sure shifting rod has some slack after engaging for and rev ,you can adjust that with your linkage.
Sorry, I may have not described it right. I do appreciate all the help I can get. This has been this way for two and half years. My marina has taken the stern drive off two seasons in a row and each time it comes back from the rebuilders it?s the same. First they changed my clutches then some bushings. At about 3500-4000 rpm It seems to jump out of gear and screams up to 5500 rpm, when it does this I pull back on the throttle never touching the gear shifter, then I accelerate again and it works until it gets to that higher rpm again. I hope that explains it better.
I should mention that the marina changed my pro from the standard left hand drive to a right and it was ok until I lost that prop and they changed it back to the original left because they could not find another right-handed prop. Is this a clue?
I agree with captmello,that what I suspected,you may have wrong prop.
I would go with 21 pitch .
Direction of rotation is not important for single engine boat,and easy changed on AQ280.
A 21 pitch is a huge jump. We don't even know his speeds or rpms. Sounds like a prop to me also and I think your rebuilders should have asked if you had tried that.
Adding 1 inch of propeller pitch will reduce full-throttle RPM by 150 to 200.
Subtracting 1 inch of propeller pitch will increase full-throttle RPM by 150 to 200.
There is no direct correlation between diameter and rpm as there is for pitch. That is why you will not find any recommendations relating to it vs rpm. Diameter and rake affect different boats and different set ups differently. That's part of the black art of props. Trail and error, test, test, test...there is no way around it.
I have 6cylinder AQ170 and went to 15 1/4 X 21pitch (only 170HP)in my 21ft Wellcraft.
It also depends at what RPM you going on plane.
You can start with 19,but in my opinion for 350 engine ,21 will be closer.
I have AQ290A (GM350)in my 26 Chriscraft Catalina,the recommended full throttle RPM 4600
thanks guy's for your help this forum is great! I found it odd too. if the problem was my drive, it would slip weather I was using a left or right handed rotation props. It did not do it when they changed rotation because it was a new prop. When I lost that prop they reverted back to the standard left hand rotation and used my original prop. I know hindsight is 20/20 but they should have picked up on that. It cost me $1,700 the first time and the bill for the second time is $2,200 which I refuse to pay. the boat is stored for the winter now, I will drive up today to get the prop off. can a prop shop test this, if yes how? I have always used the 15-17 or 17-17 prop and I get a speed of 30 to 32 mph. rpm range is 4500 to 4700. is it possible that a prop bushing only slips at high torque and not noticeable by eye.
Prop bushing is vulcanized in rubber,ones it span ,rubber and bushing becoming loose,you may be able to comeback home from your trip at slow speed,maybe high idle,and need to be replaced.
I highly recommended E-bay ,don't be afraid to buy used propellers,some are going for as low as $55.
You can easy sell your old prop as well.
