Worth mentioning that the process of sucking the oil through the dipstick tube will be A LOT faster if the oil is warm.

Yep, no need to pop a hole in filter. Unless its really cold temps the filter will be empty in a couple mins.

Guys,

OK.... So what's the deal with the in-line fuel filter?

First,,,, Is there a significant difference between the Sierra Marine in-line filter and the Mercruiser/Quicksilver unit? The QS filter was several days out from Amazon, and none of the dealers/service shops had any, so I ordered the Sierra filter.

Second.... What's the deal with the threads on the ends? In the interim, waiting for the filter to arrive (I have a timeline I'm trying to meet), I wanted to flush the existing gas in the line between the separator and the fuel rail, but I wanted a new filter in place when I did. I eventually ended up picking one up from both NAPA and Advanced Auto that were supposedly cross-referenced part. They are not. They appear to have 3/8" NPT threads in the female fitting on either end, and the connectors appear to have the matching male NPTs (I'm a toolmaker. I know my threads) but neither fitting from the Mercruiser filter I pulled from the boat will fit in either of them. They won't really even start. But a 3/8 NPT fitting will thread right into the Merc filter. What gives?

Also, as a side question... The thread sealant on the existing fittings is pretty well toast. Is teflon tape safe to use on these fittings? Is there a gasoline rated thread sealant? I failed to check while out and about, looking for a filter.

Thanks. Brad.
(937)545-8991

See:
https://www.mercruiserparts.com/bam/.../31815/6708/60

Do not use pipe thread tape on any fuel fitting. A strand getting in the fuel will ruin your day or season and wallet.

use thread sealant , on pipe threads, like permatex with teflon.
use smsll smt and a few threads down from where they start.



This is s pic of the fitting. Sure looks like pipe thread to me. Specs on link above indicate this too.

Those prefilters have been discussed on here before.
I don't think there ever has been a crossover number to the auto world discovered.
The GM apps use M16 x 1.5 threads and have an O ring seal situation.
And the Merc is a NPT setup.

My boat is an 03. When I got it 12 years ago I thought replace those, they should be cheap enough.
Now at link SB posted $73.00 list. WTF
They were like $60 back then. For that?
So I put these 100 micron with correct NPT to hose size barb.
100 micron is customary prior to pump in the racing world.
Stainless screens, cleanable.
Never could find the Merc micron rating and I cut them open there was this measly plastic tube strainer in there.
Hope I got pictures still somewhere. I'm going to look.

If not, cut your old one open and share, see what's in there.

Cheech,

I picked up a Sierra fuel filter from Amazon for ~$40. It is a direct replacement.

thwre was some considerable crud in the outgoing filter, but not near enough to be of any concern other that “Where did it come from”.

Thanks. Brad.
(937)545-8991

Guys,

Got the boat all back together. Flushed the fuel line between the separator and the fuel rail into a glass vase before making the final connection to the fuel rail. I saw zero debris or any kind. The debris I found in the fuel rail might have been from a previous time, before our ownership, when the owners might have let it go too long. Who knows. The fuel system should be clear from here forward.

Brought the boat to the house, hosed it up and fired it up. At first, it ran like crap. It seriously sounded like it was missing about five cylinders. I shut it off and double checked everything, looking for leaks, missed connections, etc… Nothing. Decided to try it again and VIOLA! It runs like a Swiss top. It must have still had air in the fuel rail that hadn’t worked it’s way through the injectors. It definitely sounds different; even at idle. It’s smoother, if nothing else. It does have a bit of an oscillation, between 650 and 700 RPM, at idle until it warms up. It seems to settle in after that, especially if I give it a couple quick throttle stabs. I had noticed this back right after having the Whipple flash done on the ECM, and about the time it went away seems about when the performance started going away. It sure the Whipple flash is doing me any good. Might be time for a real time tune, instead of through the mail.

Sooner or later, I’ll have to find the 10mm combination wrench that fell into the bilge and retrieve it. I can’t seem to locate it. I’ve tried swishing a magnetic pickup tool around under the engine, but haven’t stumbled on it yet.

We are taking it to the lake tomorrow for a full test. My fingers are optimistically crossed.

News at eleven…..

Thanks. Brad.
(937)545-8991

Hey Brad. Does the filter have 1/4” or 3/8” npt ? I know lines thensekves are 3/8”.

Here is a 1/4” from Quick Fuel. A holley co.
https://www.summitracing.com/parts/q...estionsanswers

You tomorrow.

SB,

3/8” through diameter, and the tap fits right into the holes.

Thanks. Brad.
(937)545-8991