Engine cutting out at approx. 2500 RPM

[Scooter04]

Hey everyone, as many others I have been on and off this forum for years more out of interest than needing technical help. Well the day has come and I am hoping someone of more knowledge can lend me a hand.

I have a 1998 Four Winns 205 - owned since new, has 486 hrs and looks like new. No one ever believes it's 19 yrs old now.

Engine
OMC Cobra manufactured by Volvo Penta Marine - 5.0Gi
Mod No 50FBPBYC
Ser No T01310551

Drive unit
Volvo Penta DP
Mod No 3868909
Ser No T0823858

Here is what it is doing:
Last Saturday we were out at the lake and it started right up and was running fine. Idle was normal, acceleration felt normal, and we cruised around running anywhere between 20 and 40mph. We stopped a few times, ate, moved and stopped again, etc. About 30 minutes before dark the boat would cut out when trying to plane and actually wouldn't get on plane as a result. I never actually let it die but would pull back the throttle when it started hesitating and it smoothed right out. It didn't backfire, but again out of common sense I would pull back on the throttle. For curiosity and testing purposes I would ease into the throttle ever so slowly and it would cut out about 2500 RPM. I would nail it and it would cut out at about 2500 RPM. I put it in neutral and slowly reved it up and it cut out at about 2500 RPM. Idles perfect and seems fine right up until that RPM. When running it up to 2500 RPM I may . . . and I say "may" have been hearing a whining noise. Not a bearing noise like a gimbal bearing, but I thought something a little louder than normal belts, power steering, and just the normal sounds of the motor.

A little history:
We used the boat maybe 6 times in 2015. If I am remembering correctly, it started to do this same thing (not wanting to get up on plane) the last time out in 2015 which happened to be at the end of the season. Prior to 2015, and the other 5 times out in 2015, this thing has always ran great. I didn't think too much about it and winterized it knowing I would have to deal with it in the spring. When I winterize, I drain the block and anything I can, treat the full tank, fog the fuel system, and run water/antifreeze mixture back through everything. Well life got in the way and we didn't use it in 2016. Along comes 2017 and I remembered it didn't want to get up on plane last time out. Before starting it for the first time I changed the full filter/separator and it did not seem to have water in the fuel. I changed the plugs, as I was not remembering the last time it was done. They weren't bad overall but I remember a couple of them being dirtier than the others. I changed the distributer cap and rotor. The inside of the cap was corroded like nobody's business. I thought to myself that had to be it. I poked around checked that no circuits where tripped, unplugged and plugged some things in looking for corrosion and all looked good. On the trailer, I turned the key and it fired right up. Took it to the lake, idled out of the launch area and the moment of truth . . . . gave it throttle and it ran right up on plane and ran great all day. That was 3 weeks ago. 2nd time out, it did what I described above.

The plan:
Did a lot of reading on here and of course the internet is a dangerous thing and gets your mind wondering about the million things it could be. I am suspecting a possible bad high pressure fuel pump. I started it tonight on the trailer for kicks, ran it up to about 2800 RPM and it ran smooth with no cut out or noticeable whine. I guess I am going to get a test gauge and take it to the lake to see if it will do it again, and if the fuel pressure is correct when the problem occurs. My understanding is I should be at 29psi on the high pressure side and 8 psi on the low pressure side.

On a side note, can you get any sort of trouble codes out of the PCM on this thing like an older car? Here are the numbers off the top of it: 3857632 50TBI\98CE01.

On another side note . . . the low oil pressure "beeping" alarm goes off after running around for awhile, and then slowing to an idle. Does it for a few minutes and then it stops beeping. It has done that for literally years and is my understanding from two different dealers that this particular motor has that issue.

EDIT - I forgot to mention that I also replaced the impeller for the raw water pump before taking it to the lake the first time this year. The needle on the temp gauge was at the boats normal position the two times I have had it to the lake.

I welcome any thoughts you guys may have and appreciate the help.

 

[NHGuy]

How well charged is the battery? What is the gauge showing?v Try running it with the gas cap loose in case there's a restriction in the tank vent.

 

[kenny nunez]

Have you inspected the raw water pump . The alarm may be the low water pressure signal. If that is what is happening the engine's computer is going into the protection mode.

 

[Scooter04]

NHGuy - battery is 2 yrs old and lives on a battery tender when not in the boat. It was over 12v when I put in in a few weeks ago but I don't remember exactly what it measured. I will check it again tomorrow when I get a chance as it sits and with the boat running. As far as leaving the gas cap loose, I can try that as well when I get it back to the lake. I have read about a check valve of some sort near the tank and have wondered about that as well. The thing that always gets me thinking is it was so consistent at a particular rpm when wanting to die.

Kenny - one thing I forgot to mention in my original post is that I also replaced the impeller before I took it out the first time. (I will edit) The old impeller seemed fine when I pulled it out, meaning it wasn't brittle, cracked, or missing anything off of it. I replaced it anyhow as it had been atlas 2yrs and it was already apart just to be on the safe side. Temp gauge on the dash was reading normal relative to what it normally reads. My gauge is oriented on the cool side at say 10 o'clock and hot at 2 o'clock. It ran and usually does at about 12:30 if that makes any sense. I have found some things on protection mode but don't know all the things that can trigger it, and until a week ago honestly didn't know it existed. I will double check but I believe when the alarm beeps I also get a red oil can light below the speedo.

Thanks for the suggestions.

 

[Jammer864]

deleted.

 

[Jammer864]

deleted

 

[Scooter04]

Sorry guys . . . we have been getting a lot of wind and rain, so I haven't had a chance to look into this much further other then doing a little more research on the internet. Hopefully can get it to the lake soon. Even though Jammer deleted his posts, he did get me thinking about something. Last time we had the boat out it started cutting out, or stalling, or bogging, not sure what is the best way to describe it after we came out of a no wake at idle. So we were sitting anchored, ran about 15 minutes, idled through a no wake, then when we took off out of the no wake and it wouldn't plane. Thats when I eased into it, gunned it, & revved it up out of gear and it would die out at approximately 2500 rpm. Not sure if it is significant, but just thought I would add that detail.

 

[Scooter04]

Finally had a little time to get back into this. On the trailer the fuel pressure after the high pressure pump is right at 29psi which I believe is correct for this year and set up. For the low pressure I am not 100% sure where to check it. There is a schrader valve on the top of the fuel reservoir. The fuel reservoir on this motor is at the rear left. Not a fun one to get to. When I put the pressure gauge on that valve I am getting maybe 5-6 psi. Its a little questionable as the meter I bought starts at what appears to be 4psi. Regardless it appears to be at about 5-6 psi. The low pressure pump does seem to have a bit of a whine when the motor is running. If you put your hand on it, you can feel it working and it seems to be warmer than the high pressure pump. I don't know this system so I don't know if both work all the time or if my observation is normal. I don't believe I can hear the high pressure pump and it doesn't "feel" like the low pressure pump wile idling on the trailer.

I've seen some posts on slightly different set ups where the "paint" on the inside of the fuel reservoir is flaking off and clogging a screen and causing problems. I have not come across my exact reservoir with that problem in my browsing, but it has been in the back of my mind.

So at this point on the trailer, the boat starts, idles fine, and will run up to +2500 rpm without any issue. I know the low pressure pump is making some noise, and that the low and high fuel pressure seem ok at the moment.

On a side note I believe there is too much oil in the motor as it is well above the mark on the dipstick which I checked several times. Dealer changed the oil last, so that is a bit disturbing. Will probably take a little out as I can't imagine too much oil is a good thing.

I guess I am going to take it to the lake and see if it will act up, and test the fuel pressure at that time. Even when it won't go past 2500 rpm it has always ran under that rpm fine. Hopefully that continues to be the case and I will not be going too far from the dock just in case.

 

[ab59]

What color is the Oil ? Can you drain a little of the oil from the pan ? Remember that oil floats on water . If it is an oil warning light coming on you should look that part of you engine over very good . My 5.7 has a long hose attached to the oil drain that makes draining oil very easy , maybe yours has the same. If you suddenly have a lot more oil than you should then you may be taking on water into the engine. At least check and eliminate that possibility .

 

[Scooter04]

I would describe the oil at dirty but not milky. I am assuming milky is much lighter brown. I have seen what oil looks like when rain gets into a drain pan with oil in it, and it doesn't look like that. It looks pretty much like when I drain my f150.

I am on the paranoid side, so I just completely drained to do an oil change. I will measure how much oil/liquid I drained out. On my 5.0 you pump the oil out of the dipstick. It has what basically looks like a garden hose fitting on it. The dipstick tube goes down to the oil pan drain plug location, so it does at least go to the lowest possible point and get as much oil as possible out until suction won't pull it out anymore. I figured I better do an oil change as it's the only way I will know the right amount is put in. Then I can check to make sure the level does not go up.

Edit: Well a drained out just about 8 quarts oil and my manual calls for 6. So either the dealer put in too much oil or I am taking on some water which is not going to make me happy. Will fill with 5 quarts and then start checking on dipstick until I get to the proper level. After messing with the drained oil and measuring the quantity, still would only describe color as dirty or darker than fresh oil. Fingers crossed this is not a sign of something else.

 

[ab59]

Well if it is water , hopefully not , you are in the rite place to find a cure for the problem. At least the engine is in running condition and if you caught it early you may , with help from these guys get er fixed without to much pain. I am not a professional but many here are and they are usually good at what they are doing so just keep plugging until you find the source and these guys will help you through it.

 

[ab59]

Another thought , if the engine is sensing that there is too much oil it may in fact have a shut down switch when it reaches x amount of pressure. If you have changed the oil go and give it a test drive and see if it is still showing an oil light and cutting out at 2500 rpm.

 

[Scooter04]

Made it out to the lake over the weekend. Boat got up on plane without any hesitation or bogging. Ran around probably 30-40 minutes anywhere between 2300 & 3800 rpm and didn't seem to have any problems. Low pressure fuel pump definitely whines and get's really warm to the touch. Not sure if it's normal, just an observation. Low pressure oil alarm did not come on as often or as long as last two trips to lake. It did not come on after running for any length of time and then coming to an idle which it typically does. Checked the oil level after running around and it does not seem to have changed. Hopefully that is a sign that the dealer put in too much oil and that I had just not checked it since that service. After stopping and shutting off the boat . . . . when restarting the alarm goes off, but less than 5 seconds until the pressure goes up and it stops.

Maybe the crank was aerating the oil since it was so full, oil pressure reading was off due to the aeration, engine protection mode would kick in, and I would also get the low oil pressure alarm. Fingers crossed that issues are resolved, but will wait for a couple more trips to the lake before I will be convinced since the first trip out this year we had no issues as well. Next trip I will be watching that oil level and will have fingers crossed.

Thanks for advice/comments to date! If the oil level was the issue, what a simple oversight. I'm getting to where I don't trust anyone to work an anything anymore.