Breaking In New Engine

[MelLandry]

Is there a "ckeck list" of what I need to do to break in my new 350?

Second question. I'm going from a 305 to a 350. I understand it's better to slighly overwork the engine during break-in and avoid over-reving it. I had a 19p SS prop on my 305 (and it was turning 4500, 46mph at WOT). I assume this is going to be too low of a pitch for the new 350. I plan on trying to track down a used or loaner 21-22 pitch prop for the break in, then I can tune into a new prop of the correct dimensions.

Does this sound like it makes sense to everyone? Any other break-in suggestions?

 

[Don S]

Re: Breaking In New Engine

It will not hurt a new engine to do a WOT test right at the beginning. It's actually better than being overpropped for the breakin period.
Here is a Copy and Paste for the breakin procedures from a 2002 Mercruiser owners manual

20-Hour Break-In Period
IMPORTANT: The first 20 hours of operation is the engine break-in period. Correct
break-in is essential to obtain minimum oil consumption and maximum engine
performance. During this break-in period, the following rules must be observed:
• Do NOT operate below 1500 rpm for extended periods of time for the first 10 hours.
Shift into gear as soon as possible after starting and advance the throttle above 1500
rpm if conditions permit safe operation.
• Do NOT operate at one speed consistently for extended periods.
• Do not exceed 3/4 throttle during the first 10 hours. During the next 10 hours,
occasional operation at full throttle is permissible (5 minutes at a time maximum).
• Avoid full throttle acceleration from IDLE speed.
• Do NOT operate at full throttle until the engine reaches normal operating
temperature.
• Frequently check engine oil level. Add oil as needed. It is normal for oil consumption
to be high during the break-in period.

After Break-In Period
To help extend the life of your Mercury MerCruiser power package, the following
recommendations should be considered;
• Ensure that propeller allows the engine to operate at or near the top of the specified
WOT rpm range (Refer to Specifications and Maintenance) when at full throttle with
a normal boat load.
• Operation at 3/4 throttle setting or lower is recommended. Refrain from prolonged
operation at WOT rpm.
• Change the oil and oil filter. Refer to Specifications And Maintenance.

 

[Olds Eddie]

Re: Breaking In New Engine

With the new oil formulation mandated by the EPA, I would include adding a pint of GM E.O.S. to the crankcase. It has all of the addatives that the engineers found necessary for reduced wear on metal to metal interfaces inside the engine. It comes labled 'for break-in use only' to keep the EPA dogs at bay. I use it at every oil change. I am sure that there are other brands of oli additives that do the same, but my NASCAR engine builder friend likes E.O.S. He says that true racing oils already contain the additives and is labled off road use only.

 

[Don S]

Re: Breaking In New Engine

Here is Volvo's recommendations for running a new engine for WOT rpm testing, while still maintaining proper breakin procedures.

1-Maintain idle-1,000 rpm’s until engine coolant reaches operating temperature.
2-Increase engine speeds in increments of 500 rpm’s until reaching 3,000 rpm’s. Hold each rpm for two-three minutes.
3-After the run at 3,000 rpm’s decrease speed to idle. Shift into neutral. At this time inspect the engine for fuel, coolant, and oil leaks. Make any adjustments required. CAUTION: Avoid contact with rotating belts and pulleys. Serious bodily injury may result.
4-Begin testing above 3,000 rpm’s, again increasing speed in 500 rpm increments. Do not maintain an rpm for more than three minutes.
5-At WOT do not maintain maximum rpm for more than 1 minute during the first five hours of operation.

 

[Tail_Gunner]

Re: Breaking In New Engine

CAUTION: Avoid contact with rotating belts and pulleys. Serious bodily injury may result.



8) Could you elaborate or be somewhat more spefic on that>.....:}

 

[MelLandry]

Re: Breaking In New Engine

CAUTION: Avoid contact with rotating belts and pulleys. Serious bodily injury may result.



8) Could you elaborate or be somewhat more spefic on that>.....:}

pl3aes escuse3 da tuyping... i hafd to uise myu nosew

 

[calwldlif]

Re: Breaking In New Engine

Yea elaborate,
is there a drawing?
I sure would like the manual.
I hope its a merc part.:devil: