Engine Bogging over 3k RPM

[F.PK]

2003 Tige 22I 5.7 Merc. 110 hours.
First run out since the fall, had the impeller changed about a month ago after finding out the guy that winterized my boat ran it without water and just filled up the coolant lines with coolant. Had a real boat tech do the repair. The engine runs like a top until it gets over 3000 RPM then it will bog down until I pull the throttle back. No beeping or alarms to speak of. I changed the oil and fuel filter a few weeks back. I ran the boat for a few hours like this and it was very consistent about bogging just over 3K RPM. Any suggestions as to where to start?

[ChrisSnow]

Injection or carburetor?

Could be fuel pressure either way but if carbureted you could have blocked passage ways.

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[IDBoating]

Failing rev limiter is another possibility. I had a Mercury engine that behaved like that, disconnecting the rev limiter solved it. I replaced the limiter (standalone module on the engine, there are even aftermarket replacements available) and it never occurred again. Just a thought.

[Bryan]

Did u stil-bil the fuel over the winter? I had a similar issue last spring but after adding seafoam and new gas little by little as I used it up, it went away...

[IDBoating]

Try it with minimum load (nobody behind the boat, no ballast, etc.) and maximum load (towing a couple of tubes, max ballast, etc.). Does it happen at the same RPM's? Because those two situations are radically different in terms of fuel flow despite the RPM's being the same. If the RPM's where the problem happens vary with load, go with ChrisSnow's comments and focus on fuel. If the RPM's where the problem starts are always the same regardless of conditions, then it's independent of fuel flow and I'd lean toward electrical (for example, the rev limiter I mentioned earlier).

[F.PK]

I will add some seafoam to the fuel. I was told by the guy that improperly winterized my boat that he added a fuel stabilizer, that is questionable now. If I remember correctly it is fuel injected, I can run a fuel pressure gauge and lake test it to check fuel pressure. If I add the fuel pressure gauge, what reading would be considered normal?

Would I hear some sort of alarm if I was in safe mode?

[ChrisSnow]

I will add some seafoam to the fuel. I was told by the guy that improperly winterized my boat that he added a fuel stabilizer, that is questionable now. If I remember correctly it is fuel injected, I can run a fuel pressure gauge and lake test it to check fuel pressure. If I add the fuel pressure gauge, what reading would be considered normal?

Would I hear some sort of alarm if I was in safe mode?

From memory you should get 4.0 bar or 58psi on the schrader port on top.

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[boatwakes]

F.PK, the low pressure fuel pump that resides just above the fuel filter is your problem. Prior to replacement, check the wire harness is connected to it, two pin connector. Also, have someone turn the key to the "on" position while someone else has their hand on the pump. You should feel it prime for about a second. You will hear the high pressure pump under the motor prime, but the low is very quiet and you need to have your hand on it.

[F.PK]

Got the boat out this morning with the fuel pressure gauge, it read approximately 35-38 psi when primed and while running. The PSI dropped down to 5-10psi around 3500-4000rpm when the engine started to bog. How do I know if I need a high pressure or low pressure fuel pump?

[ChrisSnow]

You could tee off and measure between the pumps. Though equally take the hose off the lp out and see if it pumps at all!
Its also possible it's your pressure regulator.

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[F.PK]

Got a call back from the Mercruiser mechanic today. They said the booster fuel pump is cutting out. I have one on order and will replace it next week. I will update y'all with the results. Thanks again.

[F.PK]

I put in a new fuel booster pump last night. Brought the boat to the lake this morning and couldn't get it off the trailer. Talked to my mechanic and he instructed me to remove the anti siphon valve on top of the fuel tank. I replaced and just priming the engine my fuel pressure was at 40, I couldn't get it above 20 psi this am. I will run the boat in the morning for the final test, but I think we found the culprit.

[F.PK]

I went to get my boat ready this morning and it smelt strong of gasoline. It was spraying gasoline in the bilge from some rusted up fuel line filter between the back hatch and engine hatch that wasn't easy to see. Maybe that's why the antisiphon valve wasn't opening due to vacuum loss between the valve and booster pump.
Although two separate mechanics instructed me to "pound out" the ball in the anti siphon valve, due to the information I found in this forum, I was able to educate myself to the indications of its purpose...keeping the bilge from filling with fuel if a fuel leak is present.
Long story short, if I would of listened to those mechanics without doing my own research on this forum, I might not be typing this right now. My boat has multiple shitty wiring splice attempts from the previous owner(my winter wiring project this year). It could have been a fatal mistake leaving the valve out and doing what I was told by the boat mechanics. So I would like to thank everyone that inputs information on this forum to help out us boat dummies that don't know the port from starboard side. Yall's information is invaluable to others safety.