Help with 383 MPI

I have a new 2006 383 MPI Mercruiser engine that sat crated for 4+ years. I installed it in my boat last month and after what I thought was a reasonably thorough pre service, started and ran it. Aside from lots of problems with the power steering that necessitated the replacement of both the ram and the pump, the engine ran real nice. This past weekend while out for a short cruise it suddenly began running like it had water in the gas. I managed to limp home (5 miles) at 1400 RPM and pulled the filter. The gas was clean. Not really surprising because the tank is new and the high test fuel was fresh. I changed the filter and reprimed. Engine started but very rough. Starboard exhaust was noticeably different from port. Shut engine down and pulled the plugs. All appeared almost like new. Did a compression test before reinstalling the plugs and got 185 to 190 which is good. Now the engine wont start at all. It only has 5 hours on it. I am very old school in terms of engine knowledge and dealing with problems and this engine has a mess of electronic stuff that is over my head but I do have spark and there is fuel up where you would attach a pressure tester between the 2 fuel rails. No alarms sounded during any of this so I assume there will be no stored error codes. Does anyone have any suggestion what I have had go on here? The boat is in a remote area on an island aprox 7 miles from mainland. Generally speaking, the local service resources are very limited in expertise so I am hoping this is something I can solve and cure with your help. I am thinking that possibly the injectors are plugged. How hard are they to pull and clean? Any and all input will be greatly appreciated.

You should start with checking your fuel pressure, You may have air in the fuel system up around the fuel rail area.

Good luck with it.

I am going to get a pressure tester and work my way thr the system.

fuel pump siezed?

Checked the rail pressure on Sat. morn and it was 38 PSI
Started with the pump at the separator and pulled, inspected, blew with air and reinstalled.
Pulled the cool fuel system.
Inspected and tested pump independantly and got 80 PSI
Inspected and tested regulator and it opens at 43 PSI
Made sure everything was clean and blown with air.
Reassembled and bench tested complete cool fuel system.
Got 43 PSI on the output end that connects with the tube that goes up to the rails.
Fuel regulator opens and system stay at 43 PSI.
Weather was bad so I will not be able to reinstall system untill next weekend.
Is it possible that some unseen tiny speck of something caused this pressure drop?
Why is there not another filter other than the fuel separator?
This motor had start and run for the first 5 hours with absolutely no problems or hiccups.

did you remove the little screen in the fuel cooler rail under the regulator?

The service book refers to and illustrates a cone shaped filter under the fuel regulator. This fuel cooler package had nothing under the regulator except the o-ring. There was one screen in each pump and there is another up on the rail assembly in the fuel pressure relief assembly. Those 3 screens are the only means of filtering that I was able to find on the entire system.

Quote:

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Originally Posted by boatnuts

The service book refers to and illustrates a cone shaped filter under the fuel regulator. This fuel cooler package had nothing under the regulator except the o-ring.

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mine was pushed down about 1/4" or more under the rail surface and took a little pic to get it out..

Thanks Buizilla - I will do a complete check for it hidden inside before reinstalling the cool fuel package. I am not really sure that it would lower the upper rail pressure because it is in the return line to the fuel separator.

Quote:

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Originally Posted by boatnuts

Thanks Buizilla - I will do a complete check for it hidden inside before reinstalling the cool fuel package. I am not really sure that it would lower the upper rail pressure because it is in the return line to the fuel separator.

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ANY restriction in that return circuit will raise the pressure past the limits of the regulator to the upper rail....

Reinspected every thing on Saturday morning. There was no little filter under the fuel pressure regulator. Reinstalled the cool fuel system back on the engine. Engine started right away and runs great. What really bugs me is I don't know what I have done. I can only assume that either something came out of one of the fuel lines when disconnected and allowed to drain in the bilge before the whole assembly was removed or my bench testing of each component with both gas and air cleared what eye doesn't see. Either way, I am finally getting to run this engine and my early impressions of it's performance are a most pleasant surprise.

First and foremost you have one bad ass boat with that said what is the difference between the moppie II and the baron?
I think I have the 24 foot baron and would like to get some advise on how to go about repowering it. It came stock with a 302, 215 hp and tr drive. any guidance or direction would be muched appreciated.

TRS?? on a 215 hp motor??? The trans and the drive are taking some power from you and since its probably a deep X the trs is like dragging an anchor behind the boat. That driveline is MAJOR overkill. if thats what you really have, drop in a takeout stock merc 454 and you will still have a pretty bulletproof setup.

There was a 215 and a 215 E. Haven't seen one in many years. If you want to do a period true resto you should just get a replacement 302. If you are not concerned with original and want to re power for performance replace the entire package [ pulley to prop nut ] with something new. The TR is a house boat drive and not a performance drive. Plus it will be brutally difficult or impossible to find parts.

boatnuts, you said you reprimed the fuel? What specifically did you do? '06 is a smart craft engine. Does it say smart craft on the engine cover? It can store codes with out an alarm. I think it is possible you had a fuel problem air leak or restriction for the initial problem. You opened the fuel and did a compression test. When it was restarted and ran rough I would have focused originally on purging the air or running the air out of the system. In my experience with new engines many times a problem is in the fuel delivery and not the engine. Hard to say from here. Glad it is working again.

Moving forward if it is a smart craft engine you need to get the merc diagnostic DDT with harness and cartridge for smart craft. It is always a witch hunt trying to troubleshoot with out the proper diagnostic equipment and assumptions.

Smart craft engines protect themselves by monitoring numerous engine functions, temperatures and pressures. It is just as possible the initial issue was a cooling one. A number of cooling issues can cause the engine to restrict available power. For example if one of your manifolds got hot it could restrict power to 5 percent which is just off idle as described. The closed cooling loop my not have been overheating thus no alarm.

Fact of the matter is there is no telling why it initially did what it did with out diagnostic scanner or a smart craft display at the dash.

More on the 215. I am guessing your boat is about a '72. Back then there were basically 3 stern drive options. Merc 1 , a Volvo or a TR. The TR was the upgrade. It did not have a transmission and shifted in the drive like the others. The E had electric shift which has popular in those years. The TRS came out shorty after. It did not shift in the gearcase it had a transmission and a much smaller propeller diameter. I referred to the TR as a houseboat drive cause that's what I mostly saw them on growing up and the prop is like a 20 diameter.

Plumb the return line after the fuel rails so that there is always flow.