BF225 - First Valve Adjustment & Oil Change

I'm doing my first valve adjustment on my 225's. Looks straight forward enough. When I last had it done by dealer they insisted on oil-change at same time as "metal shavings from valve-adjustment' can contaminate oil. The shop manual doesn't mention this, and I haven't changed my oil yet, but should I run the motor for some period of time after valve-adjustments before changing my oil/filter?

(To clarify - when I say “I haven’t done my oil yet” - I mean for this maintenance window. I plan to do it at the same time boat is out of water with all the others things. Just the valve-adjust procedure is new to me).

Ask the dealer where the " metal shavings " would come from during the adjustment.

racerone said:

Ask the dealer where the " metal shavings " would come from during the adjustment.

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my bad, not shavings - i got that confused with looking for shavings in the gear case oil. I guess “contaminated debris” was the term used. Exact quote:


“the oil can be contaminated from debris coming loose from the valves and combustion chamber, so the oil has to be changed along with the filter. “

In my experience, these engines run a loooong time before needing another valve adjustment after the initial break in ones - 30 hours, 100 hours, 200 hours. If I recall correctly, the next valve adjustment was at 1200 hours, and it didn't need much adjustment even then. And I will do the oil change at every 100 hour maintenance interval. I don't see how a normal valve adjustment would contaminate the oil.

Dirt can get into the oil. It can come from contaminated tools or from the air in a dusty environment. The oil filter should remove most of the particles large enough to cause damage, but it is probably a good practice to change the oil right after a valve adjustment.

I used to live in Reno Nevada where wind blown dust was a common occurrence. After adjusting the valves on my BF90 in my driveway, I sent in an oil sample for analysis. It came back with high silicon, which is an indication of airborne dirt contamination. I let a dealer do all subsequent valve adjustments since they did the work indoors.

This may have been an extreme situation, but it illustrates that contamination can be introduced. As for metal fragments, I doubt that unless they used a hammer to adjust your valves.

@doc_stressor - good to know as I am working outdoors. Now that I'm done with the adjustment, presumably I should run the engine for some period of time to get the oil going through the filter before I change it... would just a few minutes of runtime at idle be enough?

So I did the valve adjustment procedure today on one motor (~600hrs) - I used a gap-tool towards the smaller of the tolerance side (0.203mm for intakes and 0.279 mm for exhaust.) manual says 0.20 - 0.24mm IN, 0.28 - 0.32). The intakes were all perfect and didn't need adjusting, however the exhaust side were all gapped to the same 0.20-ish setting as the intakes. Was last done by dealer. are the exhaust-side less critical and therefore they just set them the same? I set them up per manual, but it just seemed odd that it was done that way.

It's not uncommon for exhaust valves to get tight as the components wear. If they are tight, you can assume that they will continue to get tighter. So you want to adjust them to the looser end of the specification.

As far as changing the oil goes, just run the engine at idle until it reaches normal operating temperature. Then shut it down and change the oil.

Just did my other engine today (190hrs), this was it's first Valve-Adjustment. Similar result with other one - Intakes were perfect and exhausts were all tight. Adjusted to spec.