Power head causing lower unit problems?

Hi i have had problem with water in my lower unit since the powerhead was rebuilt 3 yrs ago.The lower unit has been resealed pressure and vacum tested 5 different times including the last time by or own Gearcase man.I talked to Eddie today and we are kind of out of ideas.He said he saw once in all his years a rebuild where the lower bearing carrier was not tightened and this allowed the bearing carrier to runout wich caused the drive shaft to runout and leak at the top seal.Has anybody else seen this or do you have any ideas what might be causing this. Thanks Sam 1993 lohnson 200 gt vjsletc P.S. The engine rus great


Modified by sampark at 12:36 PM 11/8/2010

I'd replace the complete drive shaft bearing assembly under the H20 pump. And also the O rings on the shift rod assembly. Those could be leaking. They are very small but it does happen.

Thanks for the reply Fred but I am sure Gearcase man took care of that when he had it.But just out of curiosity could a gearcase still pressure test and vacum test ok if those were bad. Thanks Sam

I guess the only real way to test such a fault is to swap complete gear cases with another one, that will prove 100% what it is.

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by ChampioNman &raquo;</td></tr><tr><td class="quote"> I'd replace the complete drive shaft bearing assembly under the H20 pump. And also the O rings on the shift rod assembly. Those could be leaking. They are very small but it does happen. </td></tr></table> Fred, This case was perfect from front to back. Everything was checked. We have done everything we know to do on this one and hoping someone might have an idea on what we've overlooked. Anyone with a thought please chime in, the gearcaseman is stumped! http://www.bassboatcentral.com/smileys/USA1.gif

If it leaks while running, yet pressure and vacuum checks OK when static, try replacing the upper driveshaft bearing housing with a new one. Inspect the sealing surfaces of the driveshaft also. A worn d'shaft bearing can cause a wobble while under load even though the seals do their job when tested at rest.

Are the bolt holes in the gearcase wallowed out by chance? Perhaps using the factory gearcase alignment bolts can help keep the driveshaft centered on installation.

Though I haven't run across it, a worn propshaft needle bearing could also cause a wobble and thus a leakage while running.

One other thing I've seen is a slightly bent shift rod or worn motor mounts that puts a side load on the rod, compressing one side of the o-ring(s) and unloading the opposite side allowing a small amount of water inside. Use a magnifying glass to check the o-ring area of the shift rod for worn area (usually on one side), pits, or roughness. Salt water motors used infrequently may have small pitted areas in the middle of the sealing area.

Good luck, let us know what you find out.

Seahorse, Thanks for they repley.The bolts in the gear case look good,not sure about motor mounts i will check them.I am sure Gearcase man checked the bearings.I think from here i my just try a new unit. Thanks Sam

The lower motor mounts can be pushed outwards slightly from salt buildup inside the rubber area and that puts a strain on the shift rod. With the gearcase removed, look up the shift rod hole in the midsection and see if it is inline with the swivel bracket steering shaft inner diameter. If not in line, the lower mounts are deformed.

Seahorse we may be on to something here i pulled the shift rod and the sealing surface on the shift rod looks bad and the shift rod seems to be bent a little.I have not had a chance to check lower mount alignment yet but i will first chance i get. Thanks Sam

Seahorse is there any other way to check for bad motor mounts other than just looking from below and checking alignment.

It may be hard to explain and visualize, but look from each side of the motor at the lower motor mount. The end of the metal part of the mount where it meets the swivel bracket assembly should be flush with the edge of the motor mount cover. If you see the metal edge protrude ahead of the mount cover, then salt buildup has deformed the mount, moved the lower part of the exhaust housing away from the swivel bracket, and mis-aligned the holes around the shift shaft.

Seahorse i got a chance to look at the motor mounts and the alignment between steering shaft and extension housing this weekend they both looked good.However i did find something odd i removed the shift shaft from the lower unit and tryed to install it. It would not slide thru the cowling without a considerable amount of force once it was in and got past the bend in the shift shaft it seemed ok.I removed shift shaft and illuminated that area and it is clear looking up from the bottom that the oblong hole that accomatades the shift shaft is all wallowed out(like it is rubbing under a load) on the upper right corner.Now remember this all started after the power head was rebuilt.Could the block be out of alignment?If the upper motor mounts were bad would the powerhead torque and cause side loading on shift shaft? Thanks for all your help i really feel the problem has to do with this shift shaft.

Seahorse, Eddie Pope or Fred any thoughts on my last post reguarding shift rod alignment. Thanks Sam

It's possible that the uppers are worn out. When the head gets put on the exhaust housing there is threaded bolt on the rear that lines up the head plus it also lines up on the the drive shaft. the front side of the block has two threaded studs that drop into the exhaust housing so it is pretty tough to mess that alignment up. To check the uppers you'll have to pull the head.
It may be easier and quicker to drop the lower and replace the cover and seal assembly (5006241) and put on a new grommet (321008) and see if that works.

Fred the lower unit is off.I removed shift rod from lower unit and tried to install just the shift rod and it binds going into the lower power head section right below where it connects to the shift shaft.Also the olong hole the accepts the shift shaft is all worn out in one corner like it is rubbing there under a load. Thanks Sam

Gotcha, Kind of hard to visualize but sounds like when the head was torn down one of the grommets on the linkage is missing and the keeper may have been inserted up side down.

Sam, I'm going to go out on a limb here and say I don't think so. The leverage factor in this situation makes me think this is not likely. You would have to bend the rod more than that to produce that much water intake. http://www.bassboatcentral.com/smileys/stirthepot.gif

Fred i am sorry you lost me. Grommets and keepers for shift shaft? Thanks Sam

Sorry Sam, I was referring to the cover plate and grommet for the shift rod on the lower, Seahorse had mentioned a while back about salt build up on the shift rod housing and it kind of stuck in the brain. For $40.00 it would be a quick test and you'd know you have new everything there. It comes with O rings and gasket and the grommet seals the lower to the shift rod hole on the exhaust housing.

Thanks for all your help on this guys i will let you no in the spring how i make out.Getting cold up here time to but the boat away.