2001 Sea Ray Sunsport 280 - Starboard engine low RPM

J

jmanteu1

Member
Jul 6, 2014
37
Lake St. Clair, MI
Boat Info
280 Sunsport 2001
Engines
Twin 350 Mercruiser
Hello group,

You have helped me in the past as im a relative novice to boat mechanics so im coming back to the well...

I have a 2001 Sea Ray Sunsport 280, twin 350 Mag MPI Mercruiser engines, mechanic maintained, oil change every year etc. So I had it put in on May 7th, drove it about 6 miles over 20 min to my marina and found out that the mechanics left one of the drain plugs out on the port side of the starboard engine... noticed the bilge pump was dumping but nothing when I shut the engines off and took a peak... figured it out when I started and saw the water pouring out of the engine, got a new plug in before running for more than a few minutes in idle.

First ride out after replacing the plug last week and I notice my starboard engine is not getting the RPMs to take off that I typically get, port side is fine. Usually I hit 3400 to 3800 RPM to get on plane, but starboard is only getting 3100 to 3200 with a lot of throttle when taking off. Holds 2900 to 3000 RPM when cruising but the throttle lever is about 2 inches past the port engine lever, they are usually pretty even.

Took it back to the storage marina/mechanic, they did compression testing, everything is fine. When you run in idle both engines hit 4000 RPM no problem, equal amount of throttle. They put a new distributor cap and wires on, didnt solve the problem.

Researching this site, some people were having Cool Fuel 3 problems and maybe fuel injectors clogged by paint? But that system seems to be on the 2005 models and up for a few years and this is a 2001. Marina mechanics want to send it to someone else because they cant figure it out. Plus everyone is swamped with little help so im sure thats part of it.

Would this have anything to do with them leaving the drain plug out? I dont think so, but it is certainly a coincidence that this boat with no engine issues (although it is a 2001) all of a sudden has power issues after this mishap.

Any thoughts or direction appreciated!

Jake
 
Id check for 42 psi of fuel at the rail. How old are the water separators? Side note.....my 320 replaced my 2000 ss with twin 350mags. You have a fun boat, they are runners!! Where at on lk st clair?
 
Cool fuel 3 modules have an internal paint peeling issue but I don’t think your 2001 boat was equipped with Cool Fuel 3 unless you have newer replacement motors.
 
Shenanigans77 said:
Id check for 42 psi of fuel at the rail. How old are the water separators? Side note.....my 320 replaced my 2000 ss with twin 350mags. You have a fun boat, they are runners!! Where at on lk st clair?
Click to expand...

Thanks for the reply, my guess is the water separators are original, I got the boat in 2014 and engines only had 200 hrs each, it was in immaculate shape.

I do love this boat, and im sad this is possibly the first major issue ive had with it. I store it at Miller Marina in the winter and keep at the Windmill Pointe Marina at the mouth of the Detroit River.

If the fuel pressure is less than 42 psi, what would that indicate to you?... honestly Ive changed a slave solenoid and done only minor mechanical repairs on boats so I dont know really what the water separators do, where the fuel rail is, or all that but I do think ive ruled out the Cool Fuel 3 clogged injector issue and they were thinking that might be the problem.

Thanks again!
 
jmanteu1 said:
Thanks for the reply, my guess is the water separators are original, I got the boat in 2014 and engines only had 200 hrs each, it was in immaculate shape.

I do love this boat, and im sad this is possibly the first major issue ive had with it. I store it at Miller Marina in the winter and keep at the Windmill Pointe Marina at the mouth of the Detroit River.

If the fuel pressure is less than 42 psi, what would that indicate to you?... honestly Ive changed a slave solenoid and done only minor mechanical repairs on boats so I dont know really what the water separators do, where the fuel rail is, or all that but I do think ive ruled out the Cool Fuel 3 clogged injector issue and they were thinking that might be the problem.

Thanks again!
Click to expand...

If those seperators havent been changed since 2014 youre long overdue. They look like oil filters down on the lower left front of the engine ( looking towards front of motor). Id change them, dump the old ones in a glass jar and see what you get. Less than 42lbs it will starve for fuel under load and not make rated power.
 
Shenanigans77 said:
If those seperators havent been changed since 2014 youre long overdue. They look like oil filters down on the lower left front of the engine ( looking towards front of motor). Id change them, dump the old ones in a glass jar and see what you get. Less than 42lbs it will starve for fuel under load and not make rated power.
Click to expand...

Thanks!
 
jmanteu1 said:
Thank you, what does the knock sensor do? Would that keep the RPM low?
Click to expand...
Knock sensors detect detonation in the engine and will retard the timing to try and prevent it. Will cause a loss of power. Generally with a bad or disconnected knock sensor you get a guardian alarm. You getting any “beeps” or a solid beep while its running?
 
Shenanigans77 said:
Knock sensors detect detonation in the engine and will retard the timing to try and prevent it. Will cause a loss of power. Generally with a bad or disconnected knock sensor you get a guardian alarm. You getting any “beeps” or a solid beep while its running?
Click to expand...

No beeps, sounds fine when its running in idle and even at high RPM while in neutral, problems only when out on the lake taking off or giving throttle, no sputtering I can detect but the other engine may be masking it. No beeps out on the lake either.
 
May the boat gods look favorably down upon me.:) Familiar with Anchor Bay, Belle Maer Harbor? Not too far from the mouth of the D river. Bring it by on Saturday after 12:30, ill be there. Ill bring my fuel pressure guage and Rinda for the ECM. Slip next to me is empty. Hows that for an offer?
 
Shenanigans77 said:
May the boat gods look favorably down upon me.:) Familiar with Anchor Bay, Belle Maer Harbor? Not too far from the mouth of the D river. Bring it by on Saturday after 12:30, ill be there. Ill bring my fuel pressure guage and Rinda for the ECM. Slip next to me is empty. Hows that for an offer?
Click to expand...

Extremely generous thank you! Right now the boat is at Miller Marina just north of 9 mile and I wouldnt be able to make it up there Saturday, im going to be a solo dad all weekend with my 7 year old (no problem) and 1 year old (problem!). I spoke to the office at Miller and passed along the info you have shared and about the fuel pressure, so hopefully they can check that. Whats the Rinda and the ECM?

Thanks again for your offer!
 
Shenanigans77 said:
May the boat gods look favorably down upon me.:) Familiar with Anchor Bay, Belle Maer Harbor? Not too far from the mouth of the D river. Bring it by on Saturday after 12:30, ill be there. Ill bring my fuel pressure guage and Rinda for the ECM. Slip next to me is empty. Hows that for an offer?
Click to expand...

Belle Maer is right around the corner from my parents, they moved into their place on N River Rd about a year and a half ago... if no progress by Saturday maybe I will try to make it up there somehow. Thanks again.
 
jmanteu1 said:
Extremely generous thank you! Right now the boat is at Miller Marina just north of 9 mile and I wouldnt be able to make it up there Saturday, im going to be a solo dad all weekend with my 7 year old (no problem) and 1 year old (problem!). I spoke to the office at Miller and passed along the info you have shared and about the fuel pressure, so hopefully they can check that. Whats the Rinda and the ECM?
Thanks again for your offer!
Click to expand...

just a code scanner for the ECM and will show some live data on a running engine
 
The mechanic said the fuel pressure was the same in both engines while running, not sure what the pressure was... hes spent 5 hours on it and cant figure it out. Sounds like they are done and are telling me to pick it up and run it until the problem gets worse and declares itself...
 
In case anyone is interested in the result of this issue, I waited about 4 weeks for a different mechanic to look at the boat and they ended up finding that 2 of the fuel injectors were bent in the starboard engine "as if someone stepped on them". Replaced and the boat is running great, just like before this mess started.
 
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