Bearcat oil

[Super Sportster]

Just a word of caution and don't take my word for this, do your own research. Modern oils have decreased the amount of zddp (zinc) in them to levels that can be trouble for older flat tappet camshaft engines. This would include the Bearcat engine. From what I've read you need 1150 ppm of zinc minimum in a quart of oil for the protection you need. Zinc leaves a coating on the metal after the oil has drained off after shut down and gives protection from wear at startup. You can purchase zddp additives and there are oils out there with the correct amount in them. I've been using Delo 400 30wt which is for diesel engines. However new diesel engines are required to have catalytic converters and now have low emission oils with reduced zddp. You might be wondering why modern engines can run with lower amounts if zddp, they use roller lifters, etc. The motorcycle industry was concerned too when these modern oils were introduced due to possible transmission problems with engines having combined crankcase and gearbox. I take this as they were worried about possible gear wear problems, again your Bearcat has a bevel gear drive to the camshaft from the crankshaft. Myself I'd rather be safe than sorry. Again do your own research and form your own opinion.

[Helmar]

Its interesting you came up with this.:Police1:
I have been using the Delo 400 since my trucking days back in the late 70's.
Back then, my truck never got shut off until it was time to service it, oil change.

I also run this in my older generator and backup generator.

Figured it was time to look back into this....
Thanks Dick.

[Super Sportster]

I don't want to see anyone ruin an engine, while parts are available for these now, later maybe a different story. Read some of the info on cam break-in for flat tappet cams, we never had to do what they are recommending now. I think if I were changing cams I'd be following these recommendations and if it's a used cam I'd use the shim buckets from the engine that it was removed from without mixing them up. I really don't think many people know or understand the changes that have been made to oils and effect it has on old iron. Make sure Joe that the Delo 400 you buy is not marked Low Emission. I have a gallon of that here. I think you'll find soon the the other will be phased out and we'll have to buy an additive.

[Craig Aho]

I was just gonna ask what oil is best for the bearcat and found this thread. So Delo 400 low emission is what I want? and straight 30 wt.? How about the lower unit gear oil any recommendations? thanks guys.

[Helmar]

That is what I use too. Delo 400 30wt.
My lower unit leaks water in after every outing so I am just using plain ol 90wt oil in it.
Not really what should be in it....Dick, you know or remember ?

[Super Sportster]

That is what I use too. Delo 400 30wt.
My lower unit leaks water in after every outing so I am just using plain ol 90wt oil in it.
Not really what should be in it....Dick, you know or remember ?

The manual calls for SAE 90wt marine gear oil, like you I've used 90wt plain automotive gear oil and have in everyone of my OB's since 1980, have never had a failure yet. The 30wt engine oil should not be "low emission" oil. The zinc level is too low.

[Helmar]

I seen some other Bearcat questions in here some place. Leaning her forward into the tub and she slobbers oil which will leak out down the leg.
Mine did that but quit....Oh Crap, Better check my oil
I hate getting old as I can't for the life of me remember what happened to stop that. I know she has oil in here.
The front cylinder would load up with a little oil and smoke the first time she fires up, but after that, NO Smoke..
No way in hell would I ever sell my Bearcat engine. Its more like, fit a boat around my motor!!.
Sips fuel, idle's slow as so you can troll behind it, tune up parts available at NAPA stores. I mean it has a Real coil, Real points (No need to go electronic ignition as I don't mine setting the points every year) and easy to care for.

[Craig Aho]

Thank you Guys for your help. I will buy some Delo 400. I am going over my motor and I think the oil sump may be over filled and that may be part of the constant drip. I am not sure where it leaks from yet. I am going to replace all the oils and work towards starting the engine. I bought it without seeing it run but bought it from our friend Bill up on Widbey Island and have no doubts about it. I may have some more questions as I proceed and am thankful to you guys and the forum for help.

[Craig Aho]

Drained the oil out of the motor and I think i will wait a few days before refilling with the new delo 400 to see if my dripping oil situation stops. The old oil was dirty. I will plan to do the same in the lower gear case.

[Helmar]

I change mine more often than I should. Same with the lower unit but because of my water leak, I have to change it all the time.

[61_express]

With my Bearcat I always use Delo or Delvac 15w40, and add some Lucas to my engine oil and gearcase. Works wonders when they sit for a while.

[Craig Aho]

Thanks for the feedback guys, I just drained my gear case and of the contents that drained 90 percent was water, almost no oil. Is there a concern there? I plan to refill with the 90wt gear oil per the manual. I have a service and parts manual but realize I would like to have a user manual as well.

[Craig Aho]

I added my new gear oil but it is a messy process since you have to put the fill screw back in while fighting with the oil trying to pour out. I also found a download online for the bearcat owners manual for 12.99 so I now have that resouce.

[Super Sportster]

Thanks for the feedback guys, I just drained my gear case and of the contents that drained 90 percent was water, almost no oil. Is there a concern there?

Defiantly a concern! Other than a cracked case there are 4 ways water will enter, bad seals on the drain/fill plugs, shift rod seal (o-ring), prop shaft seal, and driveshaft seal. I've had several of these apart and they are pretty simple to work on.

[Craig Aho]

I just put new oils in the gear case and engine but if it is a good idea to do so maybe during the winter I could change the seals you mention. My Bearcat is an F model by the way. Thank you again for your feedback it is sure nice to be able to communicate with those who have experience with this interesting old motors.