Break in time on older rebuilt motor???

[chrisross]

I've got a 1977 Merc 850 4 cylinder OB. I just rebuilt the engine with a used block and crankshaft. No new parts, pistons, etc... How many hours should I run it on 100:1 gas/oil mixture? How long before I bring it to WOT? I've already run her alternating medium to low rpm's for 1.5 hours?<br /><br />Thanks<br />Chris

 

[corm]

Re: Break in time on older rebuilt motor???

Ah Chris,<br />Thats 25-1 break in oil mix for 12 gal of gas<br />at 1/2 to3/4 speed for 1st 9 gal gas.Next 3 gal you can open it up for short bursts.<br />After the 12 gals run 50-1 mix. 1st 6gal no<br />long highspeed runs.After that run 50-1 any way you want to.It takes about 24 hrs to seat the rings on that motor.<br />...have fun...corm