Problems with brand new Mercruiser 383 MPI

[alldodge]

Check your fuel pressure at the rail, should be 43 psi at the rail

 

[Searay205]

you should easily be above 50 mph. My buddy has a Rinker 246 with 350 mag bravo III (300hp) and he does 52 mph. with 350 hp you should be above 50 mph again the boat test was a 6,000lb bow rider with head and shower. It had cats (puke)

 

[Searay205]

is it possible the timing isn't advancing. I always was under the impression (probably wrong) the ECM's are bullet proof. Bewilders me why dealer can't hook up diagnostic tool and monitor fuel map, air fuel ratio, spark advance, cylinder misfire. Unexcusable. Oh wait most dealer mechanics are nothing but monkey told monkey do. they don't understand what the sensors are communicating, how the components interact. Pull your dipstick, i assume oil level is correct. if it is the gas aint going in oil so its being burned. BTW my little Rinda tool also tells me fuel burn...... Rinda also tell % power output. Are you telling me my dumbass with a RInda tool and 15 minutes on the water can tell you more than your dealer?????? I be in touch with mercruiser headquarters.

 

[alldodge]

Funding a good mechanic is worth all they funds they need. The issue is a good mechanic. An example: there are 3 folks with VP diesels on the Formula forum which have been dealing with an shifting issue. Have had numerous VP certified Mech working on the boats, replaced all kinds of parts over the last couple years.

One owner happens across a shop not tried before and its fixed in one day. This Mech knows his stuff and knows where to look. All were certified Mech's but only the one knew enough to find out how to fix

I have digressed

I may not be right (my batting average is not that great) but your burning more fuel and this is a new motor. My guess is the fuel regulator is stuck from crud on the screen or something else. Checking pressure is easy and doesn't take long

 

[Rogerdog23]

My fuel pressure gauge isn’t with the boat so checking the pressure will take me a while to coordinate but is doable. Is that something that gets messed up at the factory sometimes? Or at this point maybe we are looking for long shots whatever the issue is. In fairness to the dealer they hooked it up to the computer very briefly when I stopped by with no appointment. Hopefully when they have more time next week to really look at it I’ll get some real answers.

No way my boat will hit 50 or better. With the 350 mag it did 41. It weighs 6700 dry. Have seen a number of other folks on the Sea Ray owners forum report around 45-47 with a similar setup. Still, I’m doing 39 right now and getting on plane is a chore. Not even close to what I think I should be getting...let alone the fuel I’m going through. It isn’t making oil. Not sure where the fuel is going...

 

[alldodge]

Is that something that gets messed up at the factory sometimes?

Unknown, just working off what your saying as findings. Not seeing your motor measuring fuel pressure by the ECM. If the screen gets clogged so the Reg is unable to release excess pressure it will build

 

[Offthepath]

What are the WOT RPMs? Is the prop correct?

 

[Rogerdog23]

Is the screen something I can easily check and access?

4900 rpm at WOT. Same outdrive and props as the 350 mag I replaced which turned up 5050 rpm. New engine has 50 more hp.

 

[alldodge]

Is the screen something I can easily check and access?

4900 rpm at WOT. Same outdrive and props as the 350 mag I replaced which turned up 5050 rpm. New engine has 50 more hp.

Wouldn't say its easy but can be done. The screen (item 14) is on the fuel cooler, under the Reg. I wouldn't even try to check before checking fuel pressure to see if it is high

https://www.mercruiserparts.com/bam/subassembly/31747/7585/50

 

[muc]

My advice to you is to start drinking heavily. Sorry, but I had to get a Animal House reference in there.

I have many hunches, to many to go through without a scan tool and fuel pressure. This is where troubleshooting always starts, unless it’s a common problem like no spark on a thunderbolt ignition system.

When it comes to problems like you have, it’s very rare to have a trouble code to lead the way. 75% of the time I use a scanner to tell me what’s right. Once I’ve ruled out what’s working right, I can look closely at the things a scanner can’t test.

Yes I've seen many many problems with new engines. They are built by humans, and people make mistakes and sometimes have a “bad” day. A problem like yours will only show up on a dyno or it out on the water. So I could see some dealerships miss it. I’ve worked for a few different dealers and at some we would do extensive testing of the boat before giving it back to the customer. Other dealers we would let the customer do the testing. Some dealers charge more so they can provide this extra service. Unfortunately some charge more because they are greedy. And unless you work there, it’s hard to tell the difference.

Yes i am worried you might cause damage. If you’re using that much more fuel, it’s not all getting burned. The excess is washing down the cylinder walls and getting in the oil. Not good.

No your not nuts. It sure sounds like you have a problem.

Searay205 I find it funny that you don’t like catalyst engines. And then ask why the dealer doesn’t monitor some parameters that are only available on a catalyst engine. I think you’re confused about what the Rinda tool is telling you with % power output. It’s NOT how much power the engine is producing. It’s telling you if the ECM is restricting how much power could be available. With this engine I’m guessing it will say 100%.

alldodge Agree that testing fuel pressure is much better than inspecting that filter. Even with the engine out of the boat it’s not easy. In the boat it almost always sucks.

50 extra horsepower won’t make a big difference in your boat, but it won’t make it worse.

 

[tank1949]

Just repowered with a 2020 Mercruiser 383 MPI and am having performance / excessive fuel burn problems.

Here are the quick details:
—24 foot Sea Ray that had a 350 Mag MPI
—Haven’t touched the props or Bravo III drive (same as before repower)
—Went from burning 11.8 gallons per hour at cruise to 17 gallons per hour (same rpm)
—Top end RPMs went down by 200 and top speed is down 2 miles per hour
—New engine has 30 hours on it and is a brand new, not a remanufactured.
—New engine added 50 horsepower (from 300 to 350)
—Boat is on a trailer so no issues with dirty hull slowing things down
—Hooked up VesselView Mobile and got an engine sensor error code. Engine or drive trim position—the input circuit for the sensor is above the valid limit.


Any ideas on what in the heck could be going on? Could the trim sensor error put it in guardian mode? Not sure that would explain the excessive fuel burn if so.

Working with Mercruiser for warranty but that is a long slow process this time of year and i want to get out on the water again.

I suspect if you meddle with anything on motor, MC will void warranty. I hate to be the bearer of bad news but I would complain to MC or who ever installed motor. And, they will used covid-19 as a delay tactic. Sad...

 

[Searay205]

I told you I was a dumbass but at least learning... I loath catalyst engines but mine don't have catalyst anymore but i still married to a couple oxygen sensors. I have gone through 3 Superformance Cobra's powered with Roush 427's. If i was going to get cancer from the smell of unburnt fuel I already have it. I could put buckets under the side pipes and catch the unburnt fuel. By the way there is one word to describe the aforementioned cars, VIOLENT I digress. 6700lbs WOW. That is a heavy boat. Again google Boattest and you can see their fuel burn at different speeds on their 6000 lb boat. . I don't know if you do have a problem. 4900 rpm vs 5000 rpm. Isn't 5000 rpm max for bravo or that may be for alpha. How do you know your fuel burn? Do you have some type of fuel consumption gauge. I think Rinda does tell you fuel burn.

 

[Rogerdog23]

Muc: Super helpful thoughts once again. Sounds like a responsible approach to figuring things out. I was worried that the scan tool wasn’t telling us much but sounds like that’s how things go when in this situation. Agree with the other person who mentioned the possibility of voiding my warranty by monkeying around with the fuel components. Their mess, will let them clean it up. Will apply more pressure Monday. Also, my Dad was a mechanic and voiced the same concerns on where is the extra fuel going. I checked and I’m not making oil on the dipstick and didn’t smell fuel in the oil but don’t know where else it could be going?

AllDodge and other folks I appreciate your thoughts as well. Thank you. I’m planning on finally getting to the boat today. If so will check the mysterious red wire and see if it is for Mercathode or other.

If I can find my fuel pressure tester, is it easy to find the fuel rail on that 383 and connect the gauge? I bought the gauge last summer when having issues with the old engine but learned I’d burnt a valve before I could test the fuel pressure. Decided a 383 would make that thing go like hell and to repower...ha...ha.....ha.

muc It sounds like MC only pays about 50 cents on the dollar for dealer labor and because of that the dealers aren’t very eager to spend a ton of time diagnosing before calling in a regional tech from MC to look at it. Any truth to that? Would you think 2 hours of diagnostic time would go a long way for a problem like mine (best guess)? Or once you go beyond the scan tool is it pretty time intensive to find the gremlin and kick those punks off campus (I’ll play Animal House references all day all night)? If this is going to turn into a MC regional thing I want to apply pressure now instead of waiting a week for the dealer to tell me it wasn’t a quick fix...

Will keep folks posted as the saga continues...

 

[Searay205]

From Chaparral 277 SSX. Yours is not performing as expected as you know Test Results

 

[Searay205]

[h=2]Test Results[/h]

600	3.6	3.1	1	3.8	3.3	273	237.3	69
1000	5.8	5	1.7	3.5	3	252	219.4	74
1500	7.7	6.7	2.7	2.9	2.5	208	180.6	78
2000	9.2	8	4.4	2.1	1.8	150	130.8	83
2500	14.7	12.7	6.3	2.3	2	167	145.2	87
3000	22.4	19.5	7.3	3.1	2.7	220	191.1	86
3500	29.9	26	9.2	3.2	2.8	233	202.5	88
4000	36.2	31.5	12.4	2.9	2.5	210	182.3	90
4500	41.6	36.1	17	2.5	2.1	176	153.5	88
5000	46.8	40.7	22.9	2	1.8	147	128	90
5415	50.8	44.2	27.8	1.8	1.6	132	114.6	95

RPM MPH Knots GPH MPG NMPG STAT. MILE NM dBa

 

[muc]

Muc:

muc It sounds like MC only pays about 50 cents on the dollar for dealer labor and because of that the dealers aren’t very eager to spend a ton of time diagnosing before calling in a regional tech from MC to look at it. Any truth to that? Would you think 2 hours of diagnostic time would go a long way for a problem like mine (best guess)? Or once you go beyond the scan tool is it pretty time intensive to find the gremlin and kick those punks off campus (I’ll play Animal House references all day all night)? If this is going to turn into a MC regional thing I want to apply pressure now instead of waiting a week for the dealer to tell me it wasn’t a quick fix...

Short answer = yes 50% is about right for some dealers.
But there is a lot that goes into this. First some states have laws that require the manufacture to pay posted retail hourly rates on warranty repairs. Some states don't. For those that don't, MerCruiser has a sliding scale that takes into account a number of things. Some of those things include. How many $"s a dealer spends with them on a yearly basis, how well equipped the shop is with all the recommended tools and the level the techs have achieved with their training.
Next is flat rate. Generally diagnostic time is only paid when a problem is found. Lets take the item alldodge brought up. The filter under the pressure regulator. To test that we do a fuel pressure test. If fuel pressure tests good, no money is paid for the fuel pressure test. Even though that test may have to be done out on the water (or on a dyno) at full throttle and load. So what happens when the pressure test points to a bad regulator/filter? If it was the filter ---- probably not covered under warranty, because filters are not a covered component. If it was the regulator? Now we get paid! We will get 1/2 hour labor for DIAGNOSIS/TEST and 1/2 hour for the PRESSURE REGULATOR replacement. So one hour labor total for a job that no tech will be able to get done in one hour.On top of this, we have to file paperwork with both the customer and MerCruiser. Also we will have to store the old regulator for 60 days (this applies to all warranty parts) in case MerCruiser wants to call it back for testing.
But not all warranty repairs are losers. An example; Trim limit switch had a covered failure. Going to get 1/2 hour for ELECTRICAL DIAGNOSIS OF TRIM SYSTEM and 2 1/2 hours for TRIM LIMIT SWITCHES/SENDER LEADS (ALPHA/BRAVO). So 3 hours for this job --- most good techs can beat that 9 out of 10 times.

So, unlike the auto industries, yes if a dealer can make 50 cents on the dollar. We are doing pretty good. This is one of the problems the marine industry faces and it gets worse if it's a boat warranty issue.

But none of this will matter at a "good" dealer. We knew when we sold the product that something like this might come up. And we made enough money up front to take care of any problems that might come up. The not so good dealer that gave you a "deal" on the parts and labor? They are going to have a hard time "affording" to be able to get the problem fixed in a timely manner.

Calling in the regional tech (we call them the TAM -- don't ask me what it stands for) I have heard that some not so good dealers will try to call them in right away, and yes those dealers will probably have to wait 2-3 weeks for them to show up this time of year, because the TAM has been called in for a simple problem too many times before. The way it usually works if the problem is more then the dealer is capable of handling. MerCruiser phone tech support will walk them through troubleshooting and have them email G3 (Mercs scan tool) files and worksheets, before a TAM will be sent out.

"2 hours of diagnostic time" I think I can count on one hand how many times MerCruiser has paid that much. If this was a retail job and you wanted an estimate up front. We would tell you that most problems are diagnosed in less then 3 hours. So we would ask for $450.00 with the understanding that we will call if we need more time.

A couple of other things, Your engine hasn't been registered in your name yet. Make sure you mention this to the dealer.
And don't put to much stock in boat test reports. One they only apply to that hull, not a good idea to do an apples to oranges comparison. Also I've been involved in a few of these "tests" and while some have been pretty truthful, some were not even close to what I saw during the test.

Fuel burn as reported on a scan tool was also brought up. Need to understand that number is a mathematical calculation done by the ECM. If you have a problem like, all the injectors are 1/2 plugged. The ECM will report that the engine is getting full fuel flow when in reality it's only getting 1/2 that much fuel. To interpret what you see an a scan tool, you need to understand how the complete system works.

 

[tank1949]

My advice to you is to start drinking heavily. Sorry, but I had to get a Animal House reference in there.

I have many hunches, to many to go through without a scan tool and fuel pressure. This is where troubleshooting always starts, unless it’s a common problem like no spark on a thunderbolt ignition system.

When it comes to problems like you have, it’s very rare to have a trouble code to lead the way. 75% of the time I use a scanner to tell me what’s right. Once I’ve ruled out what’s working right, I can look closely at the things a scanner can’t test.

Yes I've seen many many problems with new engines. They are built by humans, and people make mistakes and sometimes have a “bad” day. A problem like yours will only show up on a dyno or it out on the water. So I could see some dealerships miss it. I’ve worked for a few different dealers and at some we would do extensive testing of the boat before giving it back to the customer. Other dealers we would let the customer do the testing. Some dealers charge more so they can provide this extra service. Unfortunately some charge more because they are greedy. And unless you work there, it’s hard to tell the difference.

Yes i am worried you might cause damage. If you’re using that much more fuel, it’s not all getting burned. The excess is washing down the cylinder walls and getting in the oil. Not good.

No your not nuts. It sure sounds like you have a problem.

Searay205 I find it funny that you don’t like catalyst engines. And then ask why the dealer doesn’t monitor some parameters that are only available on a catalyst engine. I think you’re confused about what the Rinda tool is telling you with % power output. It’s NOT how much power the engine is producing. It’s telling you if the ECM is restricting how much power could be available. With this engine I’m guessing it will say 100%.

alldodge Agree that testing fuel pressure is much better than inspecting that filter. Even with the engine out of the boat it’s not easy. In the boat it almost always sucks.

50 extra horsepower won’t make a big difference in your boat, but it won’t make it worse.

The more fancier to get an extra HP, the more fnnn headaches if something goes wrong. Unfortunately, due to EPA bullshit, headaches will increase with newer OBs and I/Os technologies. I'll stick with my old technology and sleep better.

 

[muc]

The more fancier to get an extra HP, the more fnnn headaches if something goes wrong. Unfortunately, due to EPA bull****, headaches will increase with newer OBs and I/Os technologies. I'll stick with my old technology and sleep better.

I've run into more than a few people (old mechanics included) that want to go back to the carb and points days.
It was a much simpler time. But then during the 70's, people started to realize that maybe it wasn't normal to not be able to see the sun during the day. I spent time in Los Angeles, CA and Gary, IN back in those days. It was very rare to see the sun. Started getting a rash when I went swimming in the lake I would just a few years later spend all my time working on.
But then the EPA (started in 1970) began to start with their "bull****" and C.A.R.B. started to dictate how much crap was allowed to come out a tailpipe. Now I'm told (haven't been there for years) that most days you can see the sun in those cities. And I do know for a fact I can swim in the lake without getting a rash. Funny thing---- my wife's minivan has better acceleration and gets better fuel economy then my Mustang did back then.

It's possible that all those things might have happened without government intervention. We all know "big business" cares more about you and I. Then they do about profit.

So I'm happy some people can sleep good at night knowing it will be somebody's kids and grandchildren that end up paying the price for the pollution we are creating. ---- Me? I worry for them.

How does that saying go? IF you are not part of the solution, you ARE part of the problem.

 

[tank1949]

I've run into more than a few people (old mechanics included) that want to go back to the carb and points days.
It was a much simpler time. But then during the 70's, people started to realize that maybe it wasn't normal to not be able to see the sun during the day. I spent time in Los Angeles, CA and Gary, IN back in those days. It was very rare to see the sun. Started getting a rash when I went swimming in the lake I would just a few years later spend all my time working on.
But then the EPA (started in 1970) began to start with their "bull****" and C.A.R.B. started to dictate how much crap was allowed to come out a tailpipe. Now I'm told (haven't been there for years) that most days you can see the sun in those cities. And I do know for a fact I can swim in the lake without getting a rash. Funny thing---- my wife's minivan has better acceleration and gets better fuel economy then my Mustang did back then.

It's possible that all those things might have happened without government intervention. We all know "big business" cares more about you and I. Then they do about profit.

So I'm happy some people can sleep good at night knowing it will be somebody's kids and grandchildren that end up paying the price for the pollution we are creating. ---- Me? I worry for them.

How does that saying go? IF you are not part of the solution, you ARE part of the problem.

So you mean to tell me that the catalytic converters were as useless as "tits on a boar?" And, all the time I have been told that they cleaned up the air? Hum....

 

[nola mike]

So you mean to tell me that the catalytic converters were as useless as "tits on a boar?" And, all the time I have been told that they cleaned up the air? Hum....

Where did you get that from? I think he said the opposite...Not to mention that cars are infinitely more reliable than they used to be. Harder to fix and more expensive when they break, but my wife's last car went 120k miles with zero done to it outside of normal maintenance before she got rid of it because she wanted a new one...