issue with Malibu when in gear, need help

So I have an 07 malibu VLX, and all the fluids have been changed and plugs have been changed also. when the boat is in idle it runs perfect and smooth, then I put it in gear and the boat runs super rough and the drive vibrates like I have a bent prop, add a little rpms and the problem goes away. Any suggestions?

I want to say I can remember similar symptoms from a distributor cap.... Bout time to replace that? I am no mechanic though

Yeah that was my last thing. I just wanted to make sure before I went and dumped cash for nothing.

well, it's never a bad idea to replace the rotor and cap. it's pretty cheap, and good to know that it's done and in good shape. it's a basic tune-up item.

I have seen this once when a coupler was getting worn out on the drive shaft. I am not a mechanic but my boat did exactly what you were describing and that was the cause. Cheap fix.

check your rpms at idle in and out of gear.

Ok great I will try the cap first. Were would the coupler be located?

I am not a genius with boats by any means...

But I think it should be pretty easy to tell the difference in a vibration that occurs from an engine that is running rough and if it might be from the drivetrain.

I would pop the engine hatch and watch and listen to the engine while it does this vibration. I suspect that you can tell if the vibration is resonating through the drive train into the boat, or from the engine into the boat.

It is not unusual to have a very small bend in the prop that only oscillates at certain prop RPM's. Could have even hit a small to medium sized fish to get a prop off balance.

x2 and next time on the water, rev your engine at all engine speeds with the tranny disengaged and see if you can recreate the vibration with engine only. If not, then start checking the drive train and prop/prop shaft

Damn right Diggs aint no mechanic. Arn't you the guy swith the H1? Sounds like you need a high speed balance of the prop. Take it to the shop guy.

Its the drive train. I'm not going to say its the prop because this only happens when I put the boat in gear. When I add RPMs it goes away. the prop packing has been leaking lately, could that be the cause?

I would doubt a leaking shaft seal would cause vibes...A bent prop or shaft alignment issues could be like a tire out of balance...You only feel it at different rpm's! Sure it's not an idle problem...IAC valve or TPS?

I just made an appointment at my local mechanic, it seams like this fix is beyond me.lol

Any updates yet, I am having the same issue. My shaft is leaking pretty good too and thought that might be the problem.

Originally Posted by shawnmdarnell

Any updates yet, I am having the same issue. My shaft is leaking pretty good too and thought that might be the problem.

You might want to bring that boat in before you ruin your motor if your having the same problem.

So I just received a call and the mechanic is saying there is something wrong with cylinder #1. The fun begins.

Rocker imploded, and bent lift rod... no compression in the cylinder.

Is this an Indmar motor in your boat?

Hopefully you're still under warranty since it's an 07.

No im not under warranty, If im not mistaken indmar only gives a 3 year warranty.

Have your wrench bender check the riser and gasket for leaks. Typically a bent push rod is due to a valve that has stuck in the guide. This is usually either lack of lubrication or corrosion from moisture entering the cylinder when at rest.
Is it an intake or exhaust valve that failed?
What engine?

Could you feel a loss in power?

its the monsoon 340

Shawn,

There was no noticeable loss of power, just when the boat would drop into gear you could see something was off balance (engine was rocking a bit)