mjb

I have a heavy 97' 38 foot top gun. It had 502 mpi's turning max 4900 rpm using the merc HP lube. Never had any problems with the drives and there was little to no metal filings on the magnetic plugs. Over the winter I repowered with 540HP at 5400 rpm. I'm going to baby it and hope my drives last...at least thru this season.
I am considering switching to full synthetic lube. Will there be any problems swithching lubes since these drives are so old? Should I just stick with the Merc HP lube?
Thanks for the help-

Poorsche

I switched to Castrol Semi synthetic on my 1996 454's with 700 hours. Seemed less risky than jumping to straight synthetic. So far no prblems and been running it for last 250 hours.

Looks as new on every oil change too--every month.

mjb

Thanks Poorsche- the Merc HP is already semi synthetic...I am considering going to full synthetic.
Anyone with knowledge on this?
Thanks-

Badtoon

Boy where have you been anyway check Hydrocruiser's posts he has covered about every Synthetic oil made with good info. He may have info on some that haven't been made yet.

mjb

I have read many of the posts you refer to that rates the different synthetic lubes...thats not my question. I'm concerned about switching to synthetic in an older drive that has gotten use to running the semi synthetic for the last 400 hours or so. If it was a new drive I would just go synthetic and not worry about it.

Badtoon

CALLING HYDROCRUISER help us out here. I think it would help running cooler. I'm switching to full syn. on an Alpha 1 with 130 hours on it plus i'm putting more HP to it than it's ratted for.

zog02

I have a bravo from the early 90's and ran semi synthetic in it for years. I lost a bearing in it about two years ago and it threw metal all over the place. I tore it all down and cleaned everything up. When I put it all back together I put Mobil 1 full synthetic in it. I have ran over 140 hours changing the oil approx every 35 hours and have had no problems what so ever. I did flush my drive out with diesel fuel just to make sure I got all the old oil and any residual metal shavings out. I am always leary about mixing the two. I can't see fully synthetic oil doing anything but helping it. The only bad thing about full synthetic is that it does not absorb any water if you happen to have a small leak.

Hydrocruiser

Make the jump and reduce heat and friction!!

I am going to recommend you go with Amsoil Universal Synthetic Marine Gear Lube
SAE 75W/80W-90 (AGM)

I think it's the best and safest bet because they tested it with 10% water and it did very well. Additionally, it will not foam Better get your online order in!! It's now my #1 drive lube pick.


So now it's Amsoil Maine lube AGM

Redline 15W-40 or 20W-50 oil (Mobil-1 V-Twin too)

Mobil-1 oil filters

25-50 hour oil/gear lube changes....

I refuse to comprimise...only the best of the best because a maine engine or outdrive is a terrible thing to waste!