Boat vibration

Well took my boat out 1985 140

Well took my boat out 1985 140 hp mercruiser out yesterday for my test after the water pump and the upper and lower reseal was done and it ran fine.So today i deceided i was going to take my family out and the boat also ran fine.Stopped off at a beach did a little swimming and went to back up to go int the channel again had lower unit up where it was suppossed to be and it didint seem to have alot of back up power so i backed up ever so slowely and went forward and gave her the berries and a weird knocking sound started coming from my lower unit and the boat started vibrating really bad what would cause this.When i trailerd the boat i noticed in forward gear the prop spins one way and doesnt the other but in reverse gear with just a small amount of pressure it will turn both ways in neutral it spins freely like it is suppossed to could this cause my noise and vibration from something shot in the lower unit does it sound like a big fix i just had it in for 384 dollers worth of work.Does a i/o have a shear pin or something.

Pull the drive off and inspect

Pull the drive off and inspect the U joints
what does "had the lower unit up to where it was supposed to be"mean????? No shear pins in outdrives

hopefully doc he means had rea

hopefully doc he means had rear unit up to high trim not trailored all the way up with motor running

[b][i]When i trailerd the boat

When i trailerd the boat i noticed in forward gear the prop spins one way and doesnt the other but in reverse gear with just a small amount of pressure it will turn both ways in neutral it spins freely like it is suppossed

Seems the shift cable needs to be adjusted or replaced

"sorry what i meant was the ou

"sorry what i meant was the outdrive was up so that the prop didnt hit the sand when i beached her on the shore.what can happen if the trailer button was used my tilt and trim doesnt always work like it is suppossed to so i have to use the trailer button for my trim, but even when using my trailer switch and raising the lower unit all the way up the water intake is still submerged under water."

"Michael, using the trailer bu

"Michael, using the trailer button isn't so much a concern as haveing the drive raised fully and running like that, as you will damage the gibmal bearing and u-joints, besides possibly starving for water. I dont have my trim limit switch circuit connected either so I only have an up and down but always am thinking about where my drive is as I dont have a trim gauge either."

ok thank you boy there is alot

ok thank you boy there is alot to having a boat i sure am glad this site is here for new boat enthusiusts.I took the boat to the mechanic and he thought that that might be what it was so thank you for the input i like knowing what i am talking about when i talk to him

well the mech said o had exten

well the mech said o had extensive damage to the u-joints he said i was close to loosing th outdrive if i would have kept going

"Well just a update it was the

"Well just a update it was the u-joint cap that came off and knocked around inside and did all the damage.While he is at it he said he was going to replace the bellows and shift cable because they where dry rotted which i actually saw so he i going to put in new bellows,shift cable, transom seal, u-joint, yolk for 695 dollars so i think it is a good deal."

"It's a good idea to have

"It's a good idea to have it done if they're not in good shape or old, new bellows and shift cable are a great idea.. The Yolk is damaged eh? that stinks. yea 695 sounds about right, a full kit minus the yolk and joints is about 100, and your looking at about 4-5 hours labor..."