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-   -   Loosing RPM 5.7 EFI (https://www.offshoreonly.com/forums/general-q/376403-loosing-rpm-5-7-efi.html)

AllDodge 08-10-2022 05:05 PM

The Amazon pump Reg kit says it fits carb, TBI and MPI - HP pump on a carb


AFFORDABLE DIRECT FIT OEM REPLACEMENT FUEL PUMP FOR: MCM V6 Carbureted and TBI Engines 262 Mag EFI, 4.3L/LX & 4.3LH/LXH / Mercruiser Quicksilver 5.7L 350 CID MPI Alhpa/Bravo/Horizon Bobtail & 6.3L 383 CID MPI Bravo 1G700000 THRU 1G799999

SB 08-10-2022 08:49 PM


Originally Posted by AllDodge (Post 4841130)
The Amazon pump Reg kit says it fits carb, TBI and MPI - HP pump on a carb

Lol. Crazy huh ? Whole lot wrong in that, but what is right ?

AllDodge 08-11-2022 06:45 AM

Found nothing in the write up indicating what pressure the Reg is, my guess is it's 40 with OP seeing same

Edit: should be 807952A1 Mallory 9-33205

Ryanw10 08-15-2022 06:53 AM

Thanks for all the help guys, I just noticed if you zoom in on the regulator on the amazon link I attached, you can see it has 270 kpa (39 psi) labeled on the side. I just order the 200 kpa (30 PSI) regulator

Ryanw10 08-22-2022 12:09 PM

The 30 psi regulator made a big difference, but I still thinking im missing out on some RPM. The boat no longer hits a wall in the power curve around 2200 RPMs, it now pulls smooth up to 3400 rpms, but I couldn't get it any higher than that. Im thinking the timing is not fully advancing now. Im going to take it out again with the techmate to see how much advance im getting at full throttle. Im also going to verify timing is set correctly. Could someone walk me through the correct procedure to set timing on this motor?
It is a 1999 5.7 TBI EFI with bravo 3, mefi 3, and a thunderbolt distributor. What I did was jumper pins A & C on the connector, bring motor to 1800 rpms, then rotate the distributor til the crank pulley mark is between the timing cover "teeth"

SB 08-22-2022 12:16 PM

Missing ‘some’ rpm ?
Your missing a schitload (that’s a measurement) - like 1400-1600rpm.

AllDodge 08-22-2022 01:15 PM


Originally Posted by Ryanw10 (Post 4842346)
What I did was jumper pins A & C on the connector, bring motor to 1800 rpms, then rotate the distributor til the crank pulley mark is between the timing cover "teeth"

That is correct for most part. Warm motor up and once warm shut off and connect jump. Start and the MEFI 3 it should automatically bring rpm to 1200 and adjust to 8* BTDC. Recheck and if good remove jumper and motor should slow to correct idle.

Ryanw10 08-23-2022 06:19 AM


Originally Posted by AllDodge (Post 4842350)
That is correct for most part. Warm motor up and once warm shut off and connect jump. Start and the MEFI 3 it should automatically bring rpm to 1200 and adjust to 8* BTDC. Recheck and if good remove jumper and motor should slow to correct idle.

Should it be 1200 or 1800 RPMS? Also, im pretty sure I had to manually adjust the throttle to 1800 RPMs. The instructions I read said MPI models will automatically adjust, I have a TBI.

AllDodge 08-23-2022 07:45 AM


Originally Posted by Ryanw10 (Post 4842436)
Should it be 1200 or 1800 RPMS? Also, im pretty sure I had to manually adjust the throttle to 1800 RPMs. The instructions I read said MPI models will automatically adjust, I have a TBI.

MEFI 2 and 3 should auto adjust to 1200, MEFI 1 must be increased to 1800

https://cimg3.ibsrv.net/gimg/www.off...811e69d75a.jpg

Ryanw10 08-23-2022 12:40 PM

I checked the timing this morning, and with my jumper installed in the plug, it did automatically jump to 1200 rpms. At that point I checked timing with my light and the balancer mark was right between the tabs on the timing cover. I then plugged the techmate in, and it showed idle timing jumps between 4-6 degrees. I advanced the distributor to see if I could get the number closer to 8 degrees, but had no luck. I could however see the balancer mark increasing on the timing cover tabs. I took the boat out with the techmate hooked up and I could see timing increase up to 28 degrees at about 2200 rpms, and then as I would increase the throttle from there it would drop quickly to 20 degrees and just stay there for the rest of the throttle range.

I should be seeing 8 degrees at idle and 30+ degrees at full throttle correct? Possible bad ECM? The ignition module in the distributor was replaced by the marina last summer. The knock sensor has not been replaced, but is plugged in and I do not see any knock retard on the techmate.


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