5.0 efi swap out to carbs

I agree. Trying yo find a mechanic with a scanner is tough some how. Always worked on my own boat and did all the wrench turning. This new boat just made me realize what a complete shit show marine mechanics are. They are the most un realiable workers i have ever met. Even if you can finally get one to show you now have to kiss the ring and pay the bill. Uhg. Im buying a raft next time
 
Jeff Delbuono said:
I agree. Trying yo find a mechanic with a scanner is tough some how. Always worked on my own boat and did all the wrench turning. This new boat just made me realize what a complete shit show marine mechanics are. They are the most un realiable workers i have ever met. Even if you can finally get one to show you now have to kiss the ring and pay the bill. Uhg. Im buying a raft next time
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I do most of my own work also....last year my starboard engine would not rev past 4,000 rpms...the WOT rpms for my engines is 5,200.....I tried to troubleshoot the issue myself for several weeks and just could not find the problem....I finally hired a marine mechanic with a scanner and he found a fuel injector not firing....that just shows how a scanner is a very valuable troubleshooting tool....

you are correct about 'kissing the ring' of good marine mechanics....they are expensive because they know they are valuable and in high demand....

good luck.....
cliff
 
Jeff Delbuono said:
Will a fuel pressure guage show me a drop in pressure if it is my issue. What should the pressure be at At idle and WOT
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Jeff,

This is the place to start. I am concerned about the fuel sitting for 7 years. Fuel pressure on the rail should be 40-45 psi. Baseline the good engine at idle and at 2000, 3000, 4000 rpm. Then test the problem engine at those same rpms.

The pressure will drop with higher rpms but should not go below 38 psi. Based on what you have said so far.....it seems like a fuel related issue. This will prove it one way or another. Also be careful with the schrader connection since it will squirt fuel when you connect and disconnect the gauge.

If you could post the results, then we can focus on the next step.
 
So here is my 2 cents.

I would probably find another mechanic if you can - one that is Mercruisier certified or at least has the proper diagnostic tools. If you can't find a mechanic or want to DIY this is what I would do next:
  • I feel certain this is a fuel problem - even considering replacing two fuel injected engines with carburetors is nuts.
  • Any injector / throttle body cleaning you have done (this is a throttle body, not MPI, which is basically a fancy electronic carburetor) is lost because it's probably messed up again with the dirty fuel.
  • Clean the throttle body again and check/replaced all the fuel filters.
  • Hook up a portable fuel tank - I bet the problem will go away.
  • Cleaning up the 7yr old fuel is another issue - you need to get rid of the fuel and replace the fuel feed lines - those are due to be replaced regardless.
Adding to what others have said, at this point except for the portable fuel supply you have tried about everything - so it's either the fuel or you have missed something. Like others here I do most of my own work, but sometimes you just need to pull out the universal tool - your wallet. You really need some one who can do the proper diagnosis.
 
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Just a guess.

Wonder if the fuel line leading to the motor has deteriorated and collapses on itself when the engine really wants fuel.
 
Jeff,

Can you post the serial number for the engine as well? I would like to see which fuel injection system you have.
 
This is the serial # to one of them. You are 100 % correct sir. At this point i am not only kissing the ring i am taking the wallet out. Finally got a certified merc guy coming. I too feel it is a fuel problem and going to put it in his hands. I have promissed him my first born, my wife ( he said no to that ,SHOCKER ) and $ 200 an hour. He is coming today and will keep you all posted. Fired the mechanic who wanted to swap for carbs with a YOUR SERVICES WILL NO LONGER BE NEEDED....
 

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I can't remember but did anyone mention the anti-siphoning valve on the fuel tank yet?.....sometimes the ball check valve can become stuck and not open and close freely as the demand for gas increases with engine rpm.....I had this happen to one of my previous boats and it would not allow enough fuel to the engine at higher rpms and cause sputtering....since this boat sat unused for so long without fuel flow exercising the ball check valve there is a good chance it may be sticking.....

cliff
 
Little Ducky said:
Just a guess.

Wonder if the fuel line leading to the motor has deteriorated and collapses on itself when the engine really wants fuel.
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That is very possible. I had issues with my boat several years ago, it would run fine up to about 3000rpm then start hesitating and eventually would shut down like it ran out of fuel. It would not restart for 30min or so. It ended up being the fuel feed line was deteriorating from inside, looked fine out side, but the inside was just crumbling. Under high RPM the engine puts a good bit of suction on the fuel lines, mine was collapsing basically running the engine out of fuel. I replaced the fuel line, also cleaned out and rebuilt the carburetor and have had no further issues with it. This is why was was recommending a portable fuel tank to test things out.
 
Checked the pick up on my tank first thing. It is part of the tank and only has an elbow on top. Next checked for the ball check valve. It does not have one. Did the seperate fuel tank next to eliminate the tank. Ran the same. Going to def check hoses next
 

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Jeff,

Bill is correct you have Throttle Body Injection (TBI) on that motor. Which is basically a carb with two fuel injectors in it (which was a terrible design). I would start with checking fuel pressure. If you are dropping below 38 psi then you have a fuel delivery problem (compare it with the other engine). If pressure is good, I would check timing.

If your new mechanic is any good, he will have it sorted out in an hour.
 
on a side note, did you notice any difference in performance when you had the props re-pitched from 19" to 17"?.......

cliff
 
The 19 to 17 def made a difference. . You are so right. When i spoke to new mechanic he told me to stop. You are now throwing good money away with props and extra parts. Sounds like fuel or timing thing. Fingers crossed
 
ITS FIXED.............. took all your advise and fired my old mechanic and bowed to the marine mechanic gods and got one. After about 1 hour it was fixed. Old mechanic put distribuator back in and was 3 teeth off. Timing was all out of wack and wires on that motor were in the wrong firing order. Runs now like a beast.

So after 3 weeks of working on it after hours. An $800 labor bill, $1000 parts bill, $350 bill to have old props re pitched it took a merc mechanic 60 minutes with a advanced timing light to fix it for only $300 and was happy pay. So word to the wise from now on. For your boat get a boat mechanic. Thanks everbody for your help
 
Glad it's fixed - that wallet is a great tool! I hate to pay someone to work on my boat, but sometimes you just have to. I didn't realize he had removed the distributor. Regarding the other items discussed, I would definitely replace those fuel lines, your boat is 20yrs old now and those rubber lines don't last forever. I was shocked to see the condition of mine when I had issues a few years ago. Make sure you get the A1 J1527 rated for alcohol/marine use.

Now go boating!
 
....:):):).....
 
Already started to make a list of things to change out on crappy rainy days. Fuel lines are top of the list. It was the first time in weeks i slept thrue the night. Now heading out tonight to enjoy the fireworks on the raritan bay in nj
 
Jeff Delbuono said:
Already started to make a list of things to change out on crappy rainy days. Fuel lines are top of the list. It was the first time in weeks i slept thrue the night. Now heading out tonight to enjoy the fireworks on the raritan bay in nj
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please be careful.....most experienced captains will opt to not take their boats out on the water to watch fireworks because of the danger presented by other unexperienced boaters....many captains will chose to drink while driving their boats tonight going to watch fireworks....this leads to a lot of boats in a congested area with some intoxicated captains.....not a good combination...we had a young girl get killed at dusk near our marina two years ago....unfortunately she was tubing around dusk (which is illegal) and a drunk pontoon captain ran over her....they were both going to watch a fireworks show on July 4th....

cliff
 
glad to hear it's fixed. It's a good running hull once the motors spin up, isn't it?
 
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