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Post by cstoerzinger on Jul 23, 2019 13:59:43 GMT -5
Hello All,
Glad we found a new home here!
I have been chasing a problem for a few months this season after buying my 3880 last fall. My RPM's are not powering up past 3200 range and boat is getting 18 mph tops. I understand the boat is supposed to do 44-4800 rpms and up to 37 mph, obviously this is at ideal conditions and not expecting to be exact. This is happening to both engines.
I have the following Equipment
2005 Regal 3880
Twin MerCruiser 8.1S HO with Gen 3 cool fuel. Serial numbers are in the 0W090000 - 0W090200 Range
I have done the following in this order:
Replaced fuel filters, both pancake and cartridge.
Checked cool fuel cells, no paint flakes or delamination.
Replaced Impellers (not likely tied but typical maintenance.)
Checked Fuel PSI under load (3000 RPM) Stayed consistent at 40 - 42 PSI on both engines.
Replaced all plugs and wires.
Found a bad coil pack on starboard motor, which lead to replacing all coil packs on both engines.
Pulled fuel rails and cleaned all injectors on both engines. All injectors opened up and sprayed a nice triangle pattern (3 hole injectors), Fuel rail did not show any clogging or particulate.
I am still only getting roughly 3000 RPM (faria tachometers so no guarantee) and at a loss for things to try.
I am going to have a mercruiser tech hook up a computer to run diagnostics against the engines later this week but wondering if anyone else has had similar issues or ideas.
Thanks for the help!
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Post by lg260ss on Jul 23, 2019 17:13:37 GMT -5
Do you have the correct props on the boat?
Will the engine rev above 3000 rpm while in neutral?
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Post by cstoerzinger on Jul 24, 2019 7:12:32 GMT -5
Yes, I forgot to mention that.
The props were fixed (slight nicks) right before I bought the boat and were delivered off the boat where they were inspected before we launched the boat.
I also removed them two weeks ago and brought them to a local prop shop where they rescanned them. They are within spec and are roughly 21.5 X 23 Props.
The boat came at 22 X 23 from the factory.
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Post by gofast24 on Jul 24, 2019 11:39:09 GMT -5
My thoughts= Did you have a survey before purchasing the vessel? If so, sea trial and what did the surveyor indicate WOT load/RPM? If not, suggest have a OBDM connected to the engines ECU's and record the max RPM's and in our case, the amount of hours at RPM ranges (i.e. 1000-2000, 2000-3000, 3000-4000, and 4000 to 5000). Regarding the Faria gauges, ours are junk and don't rely on any readings even after "tapping" them while at sea! PS: Am originally from MKe and know you only have a few months of the year to boat, enjoy summer while you have the great weather!
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Post by cstoerzinger on Jul 24, 2019 14:33:20 GMT -5
Thanks for the good weather wishes! We are battling floods this year, so it has been interesting.
I did have it surveyed, They claimed 4200 and 4500 RPM at WOT (the lower WOT RPM on the nicked prop). We sea trialed it on a cold and rainy day, Canvas was up and I believe seas were fairly choppy, my recollection is it did get up to those RPMS via the Faria gauges. However my surveyor had little to be desired after they screwed up my Hull Number and some other basic information on the survey which almost made my financing fall through so I hold his survey as suspect to say the least. I agree with the Faria gauge issue, I believe these engines can hook up to smart craft gauges, so I will be looking into those after I fix my RPM issue. My Merc mechanics have agreed to hook up the computer on Friday, So hopefully I will have some answers then.
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Post by gofast24 on Jul 26, 2019 10:23:21 GMT -5
Thanks for the good weather wishes! We are battling floods this year, so it has been interesting. I did have it surveyed, They claimed 4200 and 4500 RPM at WOT (the lower WOT RPM on the nicked prop). We sea trialed it on a cold and rainy day, Canvas was up and I believe seas were fairly choppy, my recollection is it did get up to those RPMS via the Faria gauges. However my surveyor had little to be desired after they screwed up my Hull Number and some other basic information on the survey which almost made my financing fall through so I hold his survey as suspect to say the least. I agree with the Faria gauge issue, I believe these engines can hook up to smart craft gauges, so I will be looking into those after I fix my RPM issue. My Merc mechanics have agreed to hook up the computer on Friday, So hopefully I will have some answers then. Great having the MERC mechanics connect a OBDM to the engine ECU's! Let us know the results! Interesting, MERC's on a Regal vessel! Had to be a special order as Brunswick owns both Sea Ray and Mercury marine and Regal resists using a competitive engine (Merc's) in their vessels? We also have some WOT RPM problems on our 4160, surveyor found the port prop dinged at dry dock and recently a diver cleaning the hull bottom found the the starboard prop damaged as well. Son needs to have boat hauled this fall and get both props fixed! (Kid's) PS: I have a cousin in hudson WI, he is a retired Army Major and fully involved in the Kiwanis, name is Fred Dietz FWIW. He has a couple of boats, don't know where docked (lake or river) ? Thanks |
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Post by gofast24 on Jul 30, 2019 10:57:25 GMT -5
How did surveyor determine the WOT RPM's? The Faria Tachometers or a OBDM reader plugged directly into the OBDM ports on the engines (like our great knowledgeable surveyor did) ? The reading (4200/4500) are about perfect for your engines, except the 4200 on the damaged prop, typically a damaged prop will display higher RPM vs. the more efficient good prop able to absorb more torque and therefore lower WOT RPM's)?)
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Post by cstoerzinger on Jul 30, 2019 12:20:38 GMT -5
Sorry for the delay. Interesting, I do not know Fred Dietz, We are on the St. Croix River docked in Hudson. And yes the surveyor used the tachometers. We have had many bad prop stories over the past few years, with many dents and one port prop a total loss due to a wing damn along the Mississippi. Not sure on special order, it does have the cherry cabinets and bow thruster which were optional.
We had the computer hooked up last week. Something interesting did come up, Fuel pressure on Port engine remained at 40 PSI, but the STBD was up to 50 PSI. My mechanic and I both jumped to Fuel Regulator issues since most other things had been checked, so i have one on order for the stbd engine. We also concluded the Port engine (running 600 or So RPM lower then STBD) was the engine holding the boat back and causing the lack of Speed and RPM on the STBD. We did a cylinder drop test through the computer and showed no RPM change on 5 different cylinders, so we thought maybe the computer was bad. Swapped computers with no change, so not the expensive computer.
Fast forward to today, my mechanic talked to Mercury this morning, and they claim 40 PSI is to high for the port engine fuel pressure. The spec is wrong and they run into the issue all the time with my serial numbers. He said swap them out for new (50$ each) and retest. So I now have two new fuel pressure regulators coming in on Friday, hopefully have an answer then.
I am a bit suspicious that 50 PSI on stbd would run 600 rpm higher then the 40 PSI on port but anything is possible, the computers on these engines have been known to do some odd things.
Any thoughts are welcome, should have some answers or more questions by next Monday!
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Post by gofast24 on Aug 3, 2019 11:28:31 GMT -5
Thanks, will wait until you replace stbd fuel pressure regulator. Hard to believe that the 50 PSIG regulator is causing a 600 RPM drop in RPM from the port engine (or visa versa?) You indicated Merc specifications indicate 40/42 PSI?You indicated MERC said 40 PSI is to high for the port engine fuel pressure, what di they say about the 50 PSI? As they admitted a problem get them to give you some compensation for their defective pressure regulators when the engine was built and sold inthat condition.
Good luck and let us know how you make out!?
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Post by cstoerzinger on Aug 19, 2019 9:39:06 GMT -5
All,
To wrap up my original post for future searches.
I finally have come to a resolution of under powered 8.1s HO's on a Regal 3880.
Turns out after Changing every imaginable maintenance item, it turned out to be injectors.
I determined it was the injectors after swapping the fuel rails, to my surprise the problem moved with the fuel rail swap.
Ordered new injectors for problem side from Amazon (330$ for a set of 8) and immediately improved MPH by 10 and RPM by 1600. I swapped the other engine yesterday and now I can say my boat performs as expected. With the quick test drive I did, I achieved 30 MPH at roughly 4600 RPM. This was achieved with 10 MPH wind, Light chop, less than 1/4 tanks of gas, full water tank and empty waste tank. I did not play with trim tabs to try and improve mph/rpm.
I would recommend anyone having troubles with the 8.1s HO with the Cool Fuel III module, to replace injectors, I saw no evidence of paint de-lamination, nor had a dirty fuel rail(paint flakes/dust/dirt/etc.), and still turned out to be injectors.
Thanks for all the input, hopefully this will help someone else in the future.
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Post by gofast24 on Aug 20, 2019 10:15:12 GMT -5
Thanks for summary of solution to problem! You previously indicated that you checked injectors and they were good, nice triangular spray pattern. Who checked them and second question how many hours on your engines when this problem popped up? I have about 900 hours on our 8.1's and still original injectors, fuel pump, spark plugs, etc and starts and runs like a new engine. What I do every year is pour two cans of sea foam in to each 150 gallon tank around November every year, go out for a short ride (30 minutes) and run gen set for the same amount of time to circulate the sea foam. Yes, we do go out for a half day or so in early Dec. and then not much in Jan. / Feb. but when back into sailing in march the engines start and run perfectly. PS: Did you replace the injectors yourself or mechanic that indicated they were good?
Thanks!
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Post by cstoerzinger on Sept 27, 2019 10:07:03 GMT -5
Sorry for the delayed response. I did check the injectors with a home injector cleaning kit, it was roughly 30 bucks on amazon, although it showed that all injectors were opening and a nice triangle spray pattern, I believe the issue was in the amount of gas it could delivery per spray. I have only 250 hours on my engines, which may have to do with why the injectors were clogged. I use sea foam as well, but as I have only gone through one season with the boat, I cannot speak for the old owner. And yes I did replace the injectors myself, It took roughly 30 minutes per side.
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Post by gofast24 on Sept 27, 2019 11:13:12 GMT -5
Thanks for reply! I would suspect the ECU would have indicated rich/lean combustion conditions as a fault code but again, those damn computers  Glad you got everything worked out! Stay warm this winter, here in the ATL we are approaching the record of 90 degree+ days in a season and at 94 forcast today we will be at 84 days over 90F! Who says there isn't any global warming? Still nice to not to have to shovel any snow here. I moved to the ATL in 1986 and so far no regrets. |
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wjh
Full Member
Posts: 51
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Post by wjh on Oct 3, 2019 7:50:04 GMT -5
As I know that we have had several questions about fuel pressure on Mercury fuel injected engines before, I would love to know what was the fuel pressure after installing the new regulators?
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Post by gofast24 on Oct 3, 2019 10:38:28 GMT -5
Good question, other than after you have resolved a major problem most folks dont go back and check anything again ($30 Amazon injector test device?) From my life experience in Engine R+D, test, development, and Sales engineering I always went back to check what, if anything, had changed, but that is me . I've always been anal in that kind of stuff:) |
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