Merc engine rebuilds
 

I need some knowledge. When looking at older merc engines say within last 5-7 years it appears the 850 amd 1075s need a rebuild somewhere between 50-100 hours. Is this correct and what does the rebuild cost/entail? If top only when do you do top and bottom and why?

You are correct with your intervals. Merc recommends a complete rebuild in the 75-100 hour area. Don't hold me to it, but I believe Merc gets around 25 K or so for a rebuild. You can get them rebuilt by an independant marine builder for less than that, since Merc replaces some parts that don't need to be replaced. Give me a call if i can help you out.
Eddie

I too have read that 1075's cost 25,000 for merc to rebuild, it seems you could replace EVERYTHING in the long block including the heads, block and crank for that much, of course when You pay them to do this you are paying stupid insane prices for each part too, Smitty

We can speak from experience with over 20 boats (close to 50 motors including the 850, 1025, 1075 and 1200) from the 557cid Mercury family of motors running through our sales and service departments.

1075: We recommend springs and lifters every 50 hours. This is done in the boat at a cost of roughly $2500 per motor. It is inexpensive and people who skip it usually regret it. At 100, 150 and 200 hours a leak down test is done to determine the health of the bottom end. If it is good you carry on for another 50 hours and repeat. If you get to 250 hours you rebuild regardless. The numbers thrown around on this thread for complete rebuild are very high if nothing is broken.

850: Same as above but interval goes to 65-75 hours. The spring and lifter job is slightly more expensive than the 1075.

If you are running this kind of motor we will be running rebuild and upgrade programs again this winter. We can also rebuild your drives and transmissions in-house to get you ready for next season.

If you are running an earlier motor from this family take note of the pulleys. They are prone to failure. When they fail they make a mess. We engineered an upgraded stronger pulley kit which is available to ship or install at our shop.

[QUOTE=Double R Performance;3777683]We can speak from experience with over 20 boats (close to 50 motors including the 850, 1025, 1075 and 1200) from the 557cid Mercury family of motors running through our sales and service departments.



Double R Performance,

What is you advice with respect to the 600sci?

Thanks,

Fearless010 (Peter)

[QUOTE=Fearless010;3777935]Depending on how they are ran, top ends at 200-250 hours and completes at 400-500.

[QUOTE=Double R Performance;3777945]Thanks

Have you done many direct water intakes on singles?

These rebuild intervals are shorter than I thought they would be. How about the 525?

Michael

600's, did my top end at 250, and everything still looked good but did it anyway's,valve job, springs lifters ect., checked bottom end and looked good.

[QUOTE=Fearless010;3777954]Yes. Many of them. Each application is slightly different depending on the bottom of the boat, transom angle etc.

Tops around 250 and completes around 500.

Like to know: I heard these 250 top/500 bottom numbers for 525s too. Isn't this for motors raced and run hard? These intervals for 525s even if the motors used mildly?
Thanks, Andy

I was always told that top end or complete rebuilds at these hrs were for the guys who were doing weekend poker runs and pushing their boats to the limit every time out. Most of us don't push our boats like that therefore the hrs are irrelevant for top end/rebuild maintenance for the average high performance boater unless your always running at top rpm's.

The other problem is that with boat motors and esp salt water motors, it is usually not the engines fault that something goes wrong. I have rarely seen a motor just break, not saying it doesn happen, but not often. Usually it is something else that went wrong: cracked headers, corrosion on valve spring or stem, cooler leak, blown gasket, clogged pick up/strainer, bad fuel, etc.... and the list keeps going. Coming from a guy that boats in salt and has a lot of friends that do, I have almost never seen an engine make it to the original magic number that the manufacter claims.