300 verados choking out
 

I have triples and the center motor is breaking my balls
Scanned all 3 motors no fault codes and reset smart craft and re-sicronised
Changed spin on fuel filter
It has good 91 octane gas
The motor starts and idles fine but won't rev over 2,000 rpm under load (it chokes out) and I can't figure out why it's been to 3 different mechanics so far
Could it be throttle position sensor?
Drive by wire communication issue?
Feul delivery problem?

it chokes out as meaning the engine stalls - or engine sputters but stays running at only 2000 rpms no matter how much throttle you apply ?

Fuel pressure reading taken - what are they ?

Spark on all cylinders ?

All fuel injectors have power and pulsing ?

possible fuel injectors needing flow testing and cleaning.

Post your serial # of your engine and year. it is mandatory for proper service procedures and proper parts installed per Merc build from engine serial # runs.

It stays running but feels like it's starving
Ser # 1B531455

Are you sure it is not going into guardian mode?

Please don't laugh - I am no where an expert by ANY means -- but in the geometry of your boat and engine placement are you sure that the center engine is getting enough air??? Underway it is possible that the center engine is somehow being starved of enough air to effect good combustion.

PLEASE -- I am no expert but if the engine scan is negative - there is something else screwy going on

Sorry if this is wasting your time

3pointstar

Fuel pressure readings and how about compression numbers is always the first start to any running problems dianostics. Surely all 3 shops did this form of testing. When a Merc tech calls in to OEM Merc for assistance - the first questions they ask the tech are fuel pressure readings and compression#'s and fuel samples taken ? If no to anyone of these answer - Merc replies are - when you get all those #'s and sample of fuel call us back, Just saying.

Sounds like possible fuel pressure problems and or injectors need to be flow tested & cleaned

Is this a saltwater app ?

Plenty of info here.

http://www.veradoclub.com/

Also read under fuel pressure trouble shooting chart in this Merc FSM service bulletin info. A lot of problems are associated with FSM. I have had a couple issues with floats and reference hose myself.

http://www.marinemechanic.com/merc/d...leshooting.pdf

The regulator
in the FSM has a reference hose connected to it and the other end is
connected to the FSM cover. From the cover, it is then connected to the
intake. Check the hose from the FSM to the intake manifold. If alright,
remove the FSM cover and inspect the line from the cover to the
regulator. If the line inside the FSM were to split, or become
disconnected, fuel will be drawn into the intake causing the engine to run rich.



Ethanol in fuel breaks down plastic hose, also floats, and with no reference to pressure regulator it over fuels motor. I always keep a float assembly in stock. I have had 3 fail so far. You can change one out in about an hr or so. My engine stopped running with no codes when float did not activate lift pump twice. When one float sunk and kept lift pump running then tripped vent switch code and engine kept running.

no codes are kicked

the compression test are perfect but no flow test have been done as far as I know so that would be my next request on the running till

fuel pressure at idle ok how about under load ? restriction in the fuel line ?

Fuel pressure tests are the start to pinpoint problem areas and then move on as that is 100 % totally correct about The FSM they can be the problem child on top of fuel pumps and then possible attention to the fuel injectors. You know water that sits in the fuel injectors for any lengths of time really hurts them.

The Merc SB = Service Bulletin posted up here is helpful and of course wants fuel pressure readings as part of the diagnostics . if only I was as smart about these new outboards compared to I/O's and inboards, I guess I could write my own ticket. Anyways thought back to what I know about the FSM = fuel supply module and the problems with them on the Verado's.

The jist is most likely in the FSM is running close to dry of fuel because the float switch is stuck and or has failed. A failed float switch will not turn on the low pressure fuel pump to refill the FSM or if the float is stuck in a position, the FSM will not have enough fuel to feed the high pressure fuel pump especially at higher rpms and or basically off idle. This will cause the high pressure fuel pump in the FSM to not properly flow the correct amount of fuel to the fuel injectors - hence a lean running condition and or starving the engine of fuel giving the reasons for the restricted rpms & cough you reported.

Merc is on their 4 or 5 th generation with the float switch to prevent it from failing due to the effects of E-10 fuels and water in the fuels that attack the float switch.

Next is to clean the FSM completely out spotless - buy and install the most current float switch and then replace with new, the reference hose for the regulator and install a new seal for the cover. All of this has to be done so do not skip any of it.

Then test to see how well this has fixed your problem. If not, then possible fuel pumps ( low & high) bad and then possible fuel injectors need to be flow tested and cleaned then flow tested again to see how well they are after the sonic cleaning.

Just an FYI - I flow, test and clean fuel injectors professionally. I have the machine to do so.

Do the simply repairs first - take fuel pressure readings, test engines on the water and fuel pressure readings on the water as well to see how all of this pans out.

This form of problems in the FSM will not show any codes no matter how many times you scan the engine. Good luck and hopefully I hit the nail on the head here.

Was the 3 other repair shops that looked at your engine, were they OEM Merc certified and trained on the Verado's. The Verado is nothing like any other of the Merc outboard lines. You have to find a shop that has a lot of indepth OEM training with them.

+10

Sometimes you have to drive a long ways to find one. Bass Pro Shops, at least around here, has trained Verado Techs.
You might want to purchase a service manual with having 3 of them.

Bass pro shop in Sarasota / Bradenton performed the work last full scan etc cost me $400

Possible what I posted will get you fixed up hopefully. Bass Pro Shops charged you 400 bucks for scanning all 3 engines not one engine is this correct ???

No offense but Bass Pro and Cabela's cherry pick what to work on. Some will only touch what they sold and some will only work on boats 5 years old.. Not saying all of their stores but some of their techs keep it that way.

Hey I thought you were in CT not on the westcoast Florida ? I know who could fix you up with your Verado's but I will have to checkin with them and you. It might not be cheap either but that's the they way it is for the saltwater ocean front certified marine repair shops plus who are very current with their OEM's training..

From http://www.veradoclub.com/index.php?topic=23.0 site titled great verado dealers. Many more are on there.

Location: Fort Lauderdale area
Posts: 9963



Great Verado Dealers

« on: March 06, 2008, 05:11:34 am »



There are two that come to mind here in South Flotrida - both certified with great facilities on the water in and around Fort Lauderdale

Lauderdale Marina - Ask for Matt the service manager

Sundance Marine in Fort Lauderdale - Ask for Randy - also the service manager

Hideaway marine - Pompano - Ask for Joe

Nothing fixed that does not need it, and both will let you do some of the work yourself before hand... Cool Cool.



Re: Great Verado Dealers

« Reply #12 on: July 12, 2008, 09:30:27 am »



And certainly FCM's home - First Choice Marine in the Tamp St Pete area!

If you are going over to Ft. Lauderdale or in that area let me know. I know a Master tech and he is very good on Verado's. I will see if he will work on it after hours. If you are staying put on the westcoast of Florida I have 2 and one comes highly recommended because they specialize in Verado's.

I would try first what I posted because the FSM and the float switch are a very common problem. It still would be wise to check fuel pressures and running conditions as possible the fuel pump(s) might be bad along with a fuel injection service. Start at the FSM first then see if anything is next. I have never been on or even looked at the Verado club website to know what is good info or not.