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tick, tick, tick sound in my 2008 3.0 mercruiser

bayliner 175

New member
OK, I'm new to the forum, new to boating and just bought my very first boat. I bought it's a 2008 Bayliner 175 wth a 3.0 mercruiser engine with less than 25 hours on the engine. This boat looks showroom new. When we take it out and after running for 30 minutes or so there is a light tick, tick tick sound coming from the engine at idle. It sounds like a light valve or lifter peck but onl at idle. My question is this something normal for these engine or was the previous owners suppose to have the valves adjusted after break in. The boat runs fantasics and has plenty of pep and power. It isnt anything that alarms me but I want to see if this is a normal sound and if it isnt what should I do. Thanks in advance for any suggestions
 
Re: tick, tick, tick sound in my 3.0 mercruiser

Rattling exhaust flappers?
Is the sound comming from behind the engine, near transom?
 
Re: tick, tick, tick sound in my 3.0 mercruiser

I dont know just comes from the engine compartment. Like I said it is a lite sound and I dont think it's anything serious but I need the opinions of more experience people. Sounds are so hard to explain. Thank you for the comments but I jut dont know exactly where it is coming from. Will take the boat out again this weekend and listen more closley
 
Re: tick, tick, tick sound in my 3.0 mercruiser

I have 2008 Four Winns H180 with mercruiser 3.0 with the same noise. First I thought it was a rocker/lifter After checking it closer the noise seems to be coming from rear of engine. I think it might be the exhaust flap as was stated How would you fix it? Another question I have is with the air/fuel screw on carb. would you know how to remove cap on adjustment screw Thanks
 
Re: tick, tick, tick sound in my 3.0 mercruiser

A lot of the GM 4 cyclinder motors tick.

New, old, it is the nature of the beast with those..........

Unless it gets real loud and affects performance, just enjoy the boat!

I have had to readjust the lifters many a time to help quiet these down a bit, but on some it never seems to go away completely........
 
Re: tick, tick, tick sound in my 3.0 mercruiser

Never heard a ticking from a mechanical fuel pump, it's a lever that rides on a cam, nothing to tick there.. could be the engine is low on oil, and a lifter collapsed. Or.. someone ran it too long without water in the driveway in that case the exhaust flappers and water pump ( impeller ) in the outdrive will need to be changed and the cooling system including thermostat will need to be checked for rubber peices..

the cap on the adjustment screw is so you dont change the adjustment.
 
Re: tick, tick, tick sound in my 3.0 mercruiser

ok no noise from the mechanical fuel pump.

Once valves are set on a 3.0 you shouldn't have to reset them.
 
I had the same issue with my 3.0 TKS when it was new last summer. I have a Bayliner 175, and i was really surprised to hear such a loud--sounded like a valve tick--on the maiden voyage. Since the boat was under warranty, I took it back to the dealer and they serviced the engine. I had many responses ranging from you will need a new engine, to finally discovering it was the mechanical fuel pump ticking on the cam. Another concern was the large amount of metal shavings on the dip stick from the arm on the fuel pump wearing down. When you unplug the line from the fuel pump to the flame arrestor, the noise stopped or got much quieter. Also, the noise seemed to be louder when the engine was warm.
Mercury covered a new mechanical fuel pump, and denied they had any issues. Sure enough, 1 month later, the ticking started AGAIN! I took the fuel pump out, and the arm was showing lots of wear again. Since Mercury couldn't seem to fix my boat, I installed a Holley electric fuel pump, and problem SOLVED! Easy fix for around $200.00. After writing a letter to Mercury about my disappointment with my new engine and a request for my $200.00 repair for their faulty engineering, I was denied my claim. Needless to say, I will not be purchasing another Mercury product due to their poor customer service. It was very discouraging to buy a brand new boat with an engineering defect on the fuel pump that the manufacture simply didn't seem to acknowledge.
To everyone out there with a 3.0 TKS with the same issue (according to my dealer--it is a common issue that Mercury should recall), I would recommend an electric fuel pump install. It was very easy, and if you'd like pictures/instructions, please let me know!
It's just not worth damaging a new engine with metal shavings. I know it doesn't matter to Mercury, because by the time the engine shows damage, it will be out of warranty!!
 
thanks for posting that lpatt2020. welcome aboard.
good troubleshooting. Merc should pay for your research.

to those suggesting flappers - Merc's water shutters haven't had any metal in them for quite some time - a decade maybe
 
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