K&N Filters on M25XP ?

[Capt.Jim]

As far as I know K&N filters used to improve performance on many other engines.

Is that the reason some M25/XP models I see using them as an upgrade?

[Ekutney]

I added the K&N filter for two major reasons:
* improve performance vs the original air intake because it increases air flow with an improved filtration system.
* so I could route the manifold to it to decrease Diesel engine smell while motoring.

I read all the posts about this change and it was relatively low cost for the benefits.

[Capt.Jim]

I added the K&N filter for two major reasons:
* improve performance vs the original air intake because it increases air flow with an improved filtration system.
* so I could route the manifold to it to decrease Diesel engine smell while motoring.

I read all the posts about this change and it was relatively low cost for the benefits.

Did you notice any positive improvement in the engine power?

[Noah]

I am not sure how truly important "enhanced" air filtration is on our marine engines. But I'm no mechanic. BTW- It is very easy to route the breather hose to the the top of the original OEM can/style  air filter to eliminate oil fumes, etc.

[Ron Hill]

Guys : I agree with Noah.  The K & N filter is a nice replacement for the original Universal Air filter.

The boat environment is neither dirty or dusty and the air filter mainly provides noise reduction.  It in no way inhibits the air flow intake to the engine.

A thought

[Ekutney]

Capt. Jim,

I have not done enough motoring yet to tell if it improved performance but I'm not counting on it.

Another reason, probably my main reason, to replace the air filter was to provided a more closed route for the manifold hose to reduce the engine smell.   I could have done this with the OEM filter but it was 30 yrs old and the fit was getting a bit loose.

I am also planning to add an oil separator so I do not ever, even though it may be a long shot, have a run away engine situation.

http://c34.org/bbs/index.php/topic,8875.msg67560.html#msg67560

[Stu Jackson]

As far as I know K&N filters used to improve performance on many other engines.

Is that the reason some M25/XP models I see using them as an upgrade?

Jim,

The "improve performance" is an urban myth.

As noted, all it does is recirculate the oil breather output directly back into the engine intake.

It's a great improvement, whether one does it with the old filter, the newer old filter or a K&N.

Once I find the darned parts I bought to do it, I'll get around to it.       We did almost 200 engine hours on our trip up the coast, and I wish I'd done it before we left, 'cuz I have a lot of cleaning up to do in the engine bay.     I used Ron Hill's old "foam in a beer can" method for many years, but this is sure an improvement over that idea.

[KWKloeber]

jhim

are you talking about "improvement" of odors aboard, or more HP or other operating characteristics? 
Remember a diesel on a boat isn't anything resembling the operation of a truck diesel.

kk

[Ekutney]

The improvement I was mostly looking for was engine odor & the potential dumping of the oil breather output into my bilge.  Again the odor of the Diesel engine.  I am waiting for. JEGS oil/air separator to be delivered then will install then start the engine & see how well it improves the smell, should get done by this weekend.  Will advise of the results.

I agree it does not  matter if used with the old filter or a new K&N.   Recirculating the oil breather back into the engine intake just makes sense.  I'm also curious as to how much oil is collected in the oil/air separator.  I have read all the reviews & the main negative comment seems to be the low capacity of the unit I will use, so I am curious as to how much is created by that little 3 cylinder 21 HP boat engine.

I will post results.

[KWKloeber]

I understand your motive, I was asking Jim what he meant by "improved."
I wish RC had addressed the potential for run aways -- I have never heard of one on a boat, one in a hundred? thousand, million? 
Very small I'd venture a guess, yet there are still owners with harnesses that have no overcurrent protection (and that HAS caused fires.)  go figure

-Ken

[Capt.Jim]

I understand your motive, I was asking Jim what he meant by "improved."
I wish RC had addressed the potential for run aways -- I have never heard of one on a boat, one in a hundred? thousand, million? 
Very small I'd venture a guess, yet there are still owners with harnesses that have no overcurrent protection (and that HAS caused fires.)  go figure

-Ken

What I meant with "improvement" is that K&N filters generally claims that their product increase the horsepower on car engines. I was wondering if that was the reason some upgrade their air filter to K&N...?

[KWKloeber]

"No". :-)

kk

[Stu Jackson]

............
................................I'm also curious as to how much oil is collected in the oil/air separator.  I have read all the reviews & the main negative comment seems to be the low capacity of the unit I will use, so I am curious as to how much is created by that little 3 cylinder 21 HP boat engine.

Couple of different thoughts:

1.  I've read many stories of folks who have done this.  Most did not use filters and have had no issues.  A few did and reported that their filters lasted forever, at least in the few years they'd had 'em in.  I only recall one skipper noting his filter picked up anything measurable.

2.  That said, using my handy dandy Ron Hill "foam in a beer can" method for the past 18 years, I just didn't find all that much blow by through the breather.  Sure, there is more to clean up regularly, as I noted earlier I wished I'd done it before we left to come up here.  But it simply isn't that much, not enough to make me jump at doing it asap, and not enough for me to even consider bothering with a filter.

3.  Filter can't hurt, assuming it doesn't provide too much resistance to the oil breather output.  I just don't know technically.  Another reason I wouldn't bother.

I think Smitty did this on his C310, I'll see if I can find the link in his blog.

[Ed Shankle]

Ed K,
I unstalled a Jegs 2 seasons ago and definitely have had an improvement with the diesel odor issue. I don't have a K&N, just tapped it into the air filter cover. I don't motor a lot, but fill the reservoir about half over the season. Good investment!

Regards,
Ed

[Ed Shankle]

Guess I should have edited a bit better. I "installed", not "unstalled".....