I'm really getting tired of cleaning out the bilge from my drive oil bottles overflowing. I don't know why mercruiser ever switched from the larger round bottles to the little square ones. Whenever I run any kind of distance over 80mph my drive oil bottles push oil out the caps. I have removed the checkvalves from the bottle caps because the XR Drives had a problem pushing the front seal out , I already went through that. I don't believe that it is necessary to run pressure in the system, it only causes seal problems and we don't want that when we go on vacation. The oil needs to expand when it gets hot. I think the solution to this problem is larger capacity bottles. Is anyone else having this problem. Any ideas where I can get some larger bottles. Any input would be greatly appreciated.

Usually the problem has been air or water getting into the drive. I havn't had a single problem with mine.

Are you running a drive shower to help cool the drive? I agree with Cord. Usually foaming from not being full or water. Pressure will help keep the foam down. Just my .02.

I had a problem with my reservoir bottles puking. Turned out I had a fried pinion bearing causing excess heat. That little barf may be an indication of a deeper problem?

The have large oil bottles on ebay, do a search for Mercruiser, they are $39.99, so hit high prices first and then scroll down. If not still on there I have the item saved on my watch list.

cprperformance,
The system has to be pressurized or the bottles will puke out drive oil. Any leaks will cause the oil to rise in the reservoir also. I had a bad drain gasket and had the same problem over 3500 rpm. I understand why you took out the check valves but that's not the solution.
Dan

you got a gasket in the cap?

i am fighting the same problem, everyone has different answers, I do know oil does not expand when hot, foaming can cause overflow , and air does expand when hot , and i also have had seals changed, there must be a drive pro with a better answer?

I have the old taller style so I'm not sure if this applies. Have you checked to see the leak is not coming from the o-ring seal where the low gear lube alarm is threaded into the bottle? Mine have never leaked through the lid, but they have through the o-ring which is a simple replacement.

I would like to thank everyone for their input. After reading all of your replies I have a few ideas. After I read jcap's reply it made me scratch my head. I think you are right, the oil is not actually expanding as much as I think it is it's the foaming of the oil in the drives that is making the bottles overflow. The reason I think this may be true is because I have recently switched from mercruiser oil to redline and the problem has gotten worse. A little while back I read some posts on everyones opinion on oils, and a few people said that the redline oil tends to foam up more than mercruiser. I think this may be true. I am thinking what I need to do is to get mercruiser oil back in the drives and try to get driveshowers to work on my boat which is something I have been fooling with for years. The standard drive showers that everyone uses on V-Bottoms does not work on cat boats, I've tried them all. From about 50mph up that ride plate on the drive is out of the water, I quess I need to put some type of pickup on the back of the boat.Let me know if anyone has any ideas on this as well. I still don't know if I want to put the checkvalves back in the bottle caps, I really don't want to blow any more seals.
Thanks for the input.
CPR PERFORMANCE