FYI for V-drives

[Formula Tenn]

Just a bit of free info for those of us who like our drives on the inside, I've got a good friend with a 04 390 Seabag. Power is 496 inboards and Hurth/ZF v-drives. Problem: Won't get on plane, only turns to about 3200 RPM and a very noticeable vibration coming from the starboard drive line. at idle there was a loud clunking noise coming from the transmission. 2 different techs inspected and both thought the transmission was about to give up the ghost BUT they also both noticed there seemed to be a bit of a miss in the engine. they both suggested a minor tune up so he went ahead and did it. miss in engine is gone and so is clunking noise coming from transmission. we will sea trial this weekend to see if planning problem and vibration are gone too and i'll report those results as well. thought this might be of help to someone with similar issues.

 

[Jmwarren]

Sounds VERY typical of a 496 that needs plugs.

I couldn't believe how much better my 34PC ran with new plugs!

 

[Formula Tenn]

sea trial verified that problem is solved. i was really surprised at how smoothly and effortlessly the boat ran after replacing the plugs. went from bad transmission with a bad vibration and won't plane off to everything is fine. just by replacing plugs! i wasn't aware of this so like i said just wanted to pass along for others

 

[seadoc3]

A wonderful boat u have!!!!

 

[Formula Tenn]

i agree but it wasn't my boat having the issue. it was a good friend of mine with a much newer searag! is it wrong of me to take pleasure in telling my buddy that my ole' bird ran smoother and had less vibration than his barely used and much lower hours boat??

 

[TylerBurich]

This is so weird but on Saturday the kids and I took my wife out for her maiden voyage on our home lake. She had previously only been on the boat during the sea trial in Florida. Anywho.. boat ran perfect out to the cove. On the way back in only a couple hours later the drives were making a terrible noise and engines were running rough and cauing a vibration. I spent some time at the dock diagnosing things and to my surprise (1) spark plug wire on each engine had fallen off! I reinstalled the plug wire back on to the plugs and the engines are smooth again. I have ordered new wires for both engines. There must me clutch mechanisms that really don't like the shock loading from a misfiring engine in the v drive. Not sure why else it would cause them to make such a noise.