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.


https://cimg6.ibsrv.net/gimg/www.off...f5f066fd48.png
This is s pic of the fitting. Sure looks like pipe thread to me. Specs on link above indicate this too.


https://cimg0.ibsrv.net/gimg/www.off...987a01cbf.jpeg

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? :bong:
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. :party-smiley-048:

SB,

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

Thanks. Brad.
(937)545-8991

Deep,

God, I hope so.

Thanks. Brad.
(937)545-8991

Brad, don’t be silly. 10mm tools are never found. :wink :) Thus the million lost 10mm tools memes.


https://cimg4.ibsrv.net/gimg/www.off...648ea0125.jpeg

lol!!!

SB,

That damned shifter bellcrank bracket….. 😒

Thanks. Brad
(937)545-8991

Guys,

Getting ready to head out late this morning, and I'm thinking about fuel pressure. As stated early on, fuel pressure has been ~38lbs at idle and up to zero manifold pressure, and ~50lbs once the transition into boost has been reached. This may change now that we have the stuck injector working properly, but in the event it's still showing low.....

ATI says boost fuel pressure should be 62-65lbs. I'm reading the manual, with instructions for adjusting fuel pressure, which I can handle, but it's not specific on one point: Is this adjustment only for fuel pressure in boost condition, leaving the idle pressure at ~38lbs, or is it for the full sweep? My setup has the ATI pressure regulator.

Thanks. Brad.
(937)545-8991

ProCharger's fuel regulator systems are notoriously crappy and inconsistent. A great investment would be to install a good fuel pump, good regulator, and have a custom tune done. Talk with Smitty (Articfriends) some more. He has done many, will be great insurance, especially with a 496 engine.

Good luck testing!

At idle, with no boost (quite the opposite, under vacuum), you would expect the engine to want stock fuel pressure. The boost referenced fuel pressure is needed when you start building boost but not before.

Yeah I seen you got a Sierra.

Did you cut the old filter open?
I know it's least of your worries currently.
I just wondered if they were as chintzy as I remember inside.

Hope the injectors resolve everything!

Guys,

Oh my God…..

Smitty said it was going to be night and day. I can’t think of any other way to describe it. I don’t think the boat was running right when we bought it. It is now.

As I stated initially, we had propped down from a 28P Bravo prop to a 26P Bravo, trying to make it a bit more water sports friendly. The tattle tale said 71, but all we ever saw on it with the 28P was 67-68MPH. After propping down, the best I could get was 65, and that was at about 4700RPM or so. Today, we saw 71MPH, with the engine tickling 5100 (just shy of the 5250 rev limit I had Whipple set it to), and still had the top 20-25% of the throttle to go. I never put it on the firewall.

My wife got a video of the boat launching and throttling up, but the resolution sucks and it’s REALLY bouncy. Just suffice it to say it LEAPS on a plane, and the acceleration is off the hook.


I’m happier than I’ve ever been with this boat, and I was a pig in the mud when we initially bought it.

I need a bigger prop. Seriously….. Anybody got a 28P RH Bravo they are looking to broom? Maybe a 30? I may have to talk with BBlades about some lab work to a 28P it I can find one available.

Thanks. Brad.
(937)545-8991

Happy for you and your family brother! Mission accomplished with help from the great OSO Brethren! :circle:

Drep,

Absolutley. I had no doubt we could solve the riddle. All I had to do was accurately describe what I was seeing and hearing and follow the advice of the many great engine minds we have here on OSO.

Thanks. Brad.
(937)545-8991

Great News!!

Thats fantastic!

SB,

I beg to differ….


https://cimg5.ibsrv.net/gimg/www.off...fb33434aa.jpeg
https://cimg6.ibsrv.net/gimg/www.off...0ebb2f541.jpeg

I just couldn’t get it out. 😒

Thanks. Brad.
(947)545-8891

Guys,


Any idea what this is all about?

Thanks. Brad.
(947)545-8991

Is that a new symptom? Or was it doing that before?

Feelgood,

From previous post….

”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.”

Rhanks. Brad.
(937)545-8991

Hunting idle until warmed up usually points to a vacuum leak.

:D

Deep,

Yeah. Kinda not the same thing. Gotta love that, though.

Thanks. Brad.
(947)545-8991

Guys,

So…. Now that we’re back up to HP, I’m looking at props. I’m currently running a Bravo1 26P, and it’s not nearly enough prop. The boat leaps on plane and is just shy of the rev limiter (5250) at about 75-80% throttle. So what should I be looking for. I know props are typically a trial and error thing, but there’s a wealth of knowledge here to tap into.

I’m working on a couple of 28P options. But I’m also thinking it may not be enough. What do we know about the BravoFS props. They are available in 1” increments, making a 29P a relatively easy option. Would a 30P be too much?

Thanks. Brad.
(937)545-8991

Good job Smitty.........:ernaehrung004:......... Id run it all the way out with what you have and see where it goes before spending any money

F2,

I kinda feel like I’ve already rung it out at 5100RPM. Stock WOT is 4600-5000. I know it’s got the forged crank and rods, as I ran the numbers through Merc, but don’t want to throw a rod finding the “limits”. I think we’re already at a point we know we need more prop.

Thanks. Brad.
(937)545-8991

Guys,

Here we go. Way better video quality and starting from an idle.


What you don’t see here is that the throttle is at about 75-80% at its highest.

Thanks. Brad.
(937)545-8991

Glad you got it figured out.

I wouldn't go any bigger than a 28.

Underpsi,

Are you thinking that 28 will load the engine enough to keep the engine off the rev limiter at WOT? Or is there some other reason for the max pitch?

Thanks. Brad.
(937?545-8991

Just because the throttle lever is at 75-80% does not mean its not at 98%. Most boat's throttles are not all the way forward at actual WOT. Push it forward and see how much farther it goes and if it hits the limiter. If it does hit the limiter, then go to 28" Bravo. 2" of pitch = about 400rpms.

did I miss it,,what was the fix?

Injectors. 2 of 8 were wonky.