2006 90hp F90TLR fuel injector problem

[Ferris11]

Brought my pontoon boat a few weeks ago to my local marina mechanics due to a no start problem. 2 months previous, they had cleaned the VST tank, the filters associated with it and a basic cleaning of the fuel injectors. The boat ran OK for 3 weeks but with loss of top speed RPM from around 5500 to 4500. I tried to deal with it figuring I would get it straightened out after fall fishing was over.
The motor after 3 weeks was running more and more erratic until 6 weeks later when I encountered a no start condition.
I initially thought it might be a fuel supply issue and after searching this forum for clues I ruled out obstruction in the fuel pickup line, had the right vacuum before the low pressure fuel pump and had the right pressure after the low pressure fuel pump and I changed all filters according to the Yamaha service manual. I'm just learning and I didn't go any further and I finally took it back to my mechanics.
They diagnosed it as a high pressure fuel pump failure, they replaced it and the fuel pressure regulator. I figured great --- problem solved. I got a call today saying that they have the right pressure going to the fuel rail, they have spark, but still a no start condition. They told me they sent the 4 injectors out for a thorough cleaning, got them back, but the injectors won't fire even when bench tested with voltage, implying that I need new injectors.
My question are: What are the odds that all 4 injectors would fail in this way at the same time? If they did, what could have caused such a failure?

[fairdeal]

They told me they sent the 4 injectors out for a thorough cleaning, got them back, but the injectors won't fire even when bench tested with voltage, implying that I need new injectors.
My question are: What are the odds that all 4 injectors would fail in this way at the same time? If they did, what could have caused such a failure?

Ugly story - you have my sympathies.

I've never heard of an injector cleaning service that didn't

a. 'fire" the injectors before cleaning to determine/record "as found"
b. "fire" them after cleaning to determine/record "after"
c. provide both of those to the customer

Your shop's story is puzzling....

[boscoe99]

What are the odds that all 4 injectors would fail in the exact same way, at the same time, immediately upon the return of said injectors from an injector servicing company? With the entire fuel system having been gone through prior to the serviced injectors being installed.

About one in a billion.

But once in a billion events do happen. One in a billion times.

[rodbolt17]

actually, for running with trash/water in the fuel. fairly high.

[Nautical]

First no start was fixed by extensive fuel system cleaning.. 3 weeks later same problem ?? Has to be the fuel is contaminated. Any enemies that like sugar ?? Just kidding !!Check fuel , and I would see what is freezing up the injector pintles and see what is inside their strainers for starters.

[boscoe99]

Ugly story - you have my sympathies.

I've never heard of an injector cleaning service that didn't

a. 'fire" the injectors before cleaning to determine/record "as found"
b. "fire" them after cleaning to determine/record "after"
c. provide both of those to the customer

Your shop's story is puzzling....

Yes. Puzzling. Methinks some one is blow smoke up some one's arse.

In addition to cleaning the injectors some shops will measure the fuel flow pre and post cleaning. They also note the spray pattern as well. What does the injector inspection report indicate?

Did the shop check the injectors before they were sent out? If so, and they did not fire why did they send them? If they did fire, but now won't fire, seems that is something they should be taking up with the fuel injector servicing folks.

Has the shop confirmed also that the injector connectors have 12 volts plus on them and that the ground wire is being pulsed by the ECU?

What will be the story if and when four new injectors are installed and they malfunction as well? I pity the poor customers who have to deal with marine mechanics who do not know what they are doing.

And why oh why are there not more water in fuel sensing systems and restriction to fuel flow sensing systems installed?

[rodbolt17]

well you know how us marine mokanics are.
no training and we troubleshoot using a version of pin the tail on the donkey.

[boscoe99]

No offense meant to you or other marine mechanics. I changed my post to say

"I pity the poor customers who have to deal with marine mechanics who do not know what they are doing."

Unfortunately the customer has little way of knowing the good, the bad and the ugly. Good mechanics get painted with a black brush because of the sins of the bad. Like lawyers and politicians.

[rodbolt17]

no offense taken.
I was also trying to point out that not all techs are the same.

some actually try to learn from past jobs.
some try to further their education and knowledge on how it works and how to do it better and faster.

some have a tool box .

a good way for a customer to at least try to figure it out is simply look on the dealerships wall for training certificates, pay attention to the certificate date.

[Ferris11]

Guys,
Thanks for your response. Your experienced comments are well taken and now at least I will know what questions to ask. I will post back next week after everything is resolved.

[rodbolt17]

Friday I repaired an F115.
customer said another marina had just repaired it and now it wont start/run again.
customer dropped off a copy of the work order.
water in the gas,VST and fuel system cleaned.

date was june of 2015.

guess what I found?

water in the gas.

so much it quit running and would not restart.
cleared the VST,flushed the injectors and the fuel rail.
started the engine and let it run about 30 min.

cause of the issue? fuel tank vented cap leaking and the fuel sender gasket dry rotted.

so until the root cause gets fixed it will do it again and again and again.

goes back to any repairs done have a root cause,if you don't find and fix that the issue will come back.

[boscoe99]

So I have a question.

There is nothing that I know of in any Yamaha training materials that addresses the need to verify that a fuel system is clean before a fuel system repair is made. All to often a part, say a fuel pump, fails and gets replaced. It fails again shortly thereafter. Another fuel pump is installed. It too soon fails. What a string of bad luck. Three fuel pump failures in a row. Fuel pumps are not what they once were. Finally the mechanic gets an epiphany.

Is the mechanic supposed to innately know to purge and clean a fuel system if a part therein fails? If not, how is he supposed to know without learning via the schools of hard knocks. At the customer's or Yamaha's expense of course.

I lay some if not all of the blame on Yamaha's training, or lack thereof. But then I can't blame Yamaha if a mechanic never goes to the Yamaha school house. Where is the young mechanic to get his education on this subject?

[robert graham]

My brother-in-laws grandson stuck the water hose in the fuel fill while at dock....continued and expensive problems with injectors, filters, removal and replacement of fuel tank, etc.,etc....seems once the system is fouled with water it can be very persistent and continued problems, especially with large, under deck tanks that don't lend themselves easily to draining and flushing....Just the nature of the beast I guess?....

[rodbolt17]

mostly cause I have done this type of work since I was 15. got my first chiltons manual at age 8'
same summer I got a used mini bike with a 3.5HP techumseh with a hole in the block.

my dad had a scrap metal business so spare blocks and such were mine for the taking.

took a 6yr break from mokaniking to work as a machinist/CNC programmer for GOEX in Cleburne Tx,another 6 yr break to work as an FC in the USN.

turned 54 last week so I guess you could say I have done it once or twice.

[TownsendsFJR1300]

Anyone that wants to turn a wrench shouldn't need a book to tell them to check the fuel for debris / water, that's a given, basic stuff.. The first question I ask, how old is the fuel, was it stabilized??? 99 times out 100, it way older than a month and NOT treated.. Add water to the mix (pun intended), even worse of course..

As most issues nowadays with ethanol is fuel related, that IS the first thing I check. IE; drain carbs, look for crap, cloudy fuel, smell it, etc..

Once the receipt was shown for being 7 months old from the last repair, the fuel is likely junk (even without the water intrusion and start cleaning / inspecting from there...