MerCruiser Break-In Procedure
10-21-2005, 09:02 PM
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MerCruiser Break-In Procedure
I will be taking delivery of boat with twin MerCruiser MX 6.2 MPI's soon. I know there are probably a dozen opinions on the best method to break-in new engines. Below is MerCruisers recommendation that comes straight from the owners manual (Mercury faxed this page to me, as I don't have the manual yet).
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.
Makes sense to keep the rpm level up (at least 1500 rpm) to assure a good amount of oil is splashing around to aid in lubricating the fresh mechanicals. Same reason for not operating at one speed for long periods.
On kind of the other end of the spectrum, I have seen recommendations to run new engines HARD during break-in. The reasoning is that hard acceleration runs build more cylinder pressure and this forces the piston rings out into the cylinder bore during the critical time of wearing in the cross-hatch pattern of the final hone. This supposedly seats the rings better and in the long run you have a better running engine.
I imagine a combination of both techniques is probably best. Like anything in moderation
Comments?
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.
Makes sense to keep the rpm level up (at least 1500 rpm) to assure a good amount of oil is splashing around to aid in lubricating the fresh mechanicals. Same reason for not operating at one speed for long periods.
On kind of the other end of the spectrum, I have seen recommendations to run new engines HARD during break-in. The reasoning is that hard acceleration runs build more cylinder pressure and this forces the piston rings out into the cylinder bore during the critical time of wearing in the cross-hatch pattern of the final hone. This supposedly seats the rings better and in the long run you have a better running engine.
I imagine a combination of both techniques is probably best. Like anything in moderation
Comments?
