Noisy engine 3.0 mercruiser TKS

[Logan1500]

I have a 85 Larson with a 3.0 mercruiser. It has had a ticking noise in it since June or July. The ticking noise, (sounds similar to a lifter) quits under a load.

When I took it to get it winterized the mechanic said it sounded like it could be a couple of different issues.

The first being that the flywheel could be loose.

The second being a main bearing.

I know the main bearing would require tearing into the motor to fix.

I was told that the motor would have to be pulled to check to see if the flywheel is loose. (I am having a few starter issues such as dragging and grinding).

Is there any way to check the flywheel without taking the motor out?

Thanks for looking.....

John

[FAST FRED]

Pull the starter and usually you can see the edge of the flywheel.
If the teeth are chewed or you can wobble the flywheel while prying with a big screwdriver, its remove time.

FAST FRED

[glassman]

You also should look at the exhaust it has a flapper in the lower pipe and when the pin or the flapper breaks it justs flops in the pipe , you said it better under a load ,try removing the exhaust hose and run the engine ,its somthing to try

[gonzo]

A worn flapper would behave just like that

[cwc]

You can get a stethoscope "kida like what a doctor uses to hear your heart"
from your local automotive store. Try and pinpoint where its coming from
anything other than lifters should be quite noticable. Internal problems are the hardest to find, so if you cant find it,its prob. inside.

[jpatt2020]

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!!

[SNYIRADY]

would be interested in pics and more info on your fuel pump changeover. I have a Sea Ray 180 with a Mercruiser 3.0 that has a faulty fuel pump and i want to change over to an electric - whatever tips you can give would be welcome..!
thanks, Steve

[gonzo]

An electric fuel pump is not a direct change over. You need to have a spark proof pump. The line between the pump and the carburetor must be metal or braided for safety. The pump will need a relay connected to the ignition to run. There has to be a safety switch run by the oil pressure, so the pump stops if the engine dies.

[SNYIRADY]

Gonzo, appreciate your input. i assume anything marine-rated would be spark proof? but i am living in Cambodia and finding marine-cert parts for anything is proving difficult. We are limited mainly to automobile parts and are there any particular car engines (Chevy inline V6 for the manual fuel pumps?) that we can pull an electric pump off of and adapt for the Merc3.0?
Metal fuel lines are no problem, good idea. Can you describe the oil pressure safety switch - where is it located and is this an easy mod? thanks for your advice. SN

[Submarine Tom]

jpatt2020,

That problem didn't show up in your pre-purchase research?

Too bad.

-Tom

[SNYIRADY]

what problem - the fuel pump issue? Was told it was a carb problem when i bought the boat - which had been winterized and then garaged for the last 5 years before i got it.

[gonzo]

It should be much easier to change to a a standard mechanical pump. The oil pressure switch is On when there is oil pressure and Off when the pressure drops. If the engine stalls or dies, the pump stops. Otherwise, if you have, for example a fuel leak, the pump will keep on going and empty the fuel tank into the bilges.

[SNYIRADY]

That would be my main concern - and with wife and kids using the boat i need something safe and uncomplicated. Any automotive manual fuel pumps you recommend? SN

[gonzo]

No, they are not the same even though they bolt on. Automotive fuel pump dump the fuel is the diaphragm breaks into the bilges. Marine pumps have a fitting for a hose that dumps the fuel into the carburetor. How hard is it for you to get a new pump through customs?

[powerabout]

engine has been fine for 40 years and now Merc invent a new problem
I find it hard to believe a dealer cant get a w/tee on the pump
try a new dealer

[powerabout]

or buy a old style pump from a engine wrecker/salvage yard assuming its the pump

Only thing is I dont know is it the pump or cam issue?

[jpatt2020]

Submarinebob: Unfortunately, I didn't see anything in my pre-purchase research. I wasn't even thinking about engine issues--this GM 3.0 block has been around for decades with no issues. Most of my research was on the boat itself.

MY ISSUE WAS THE FACT THAT MERCURY HAD NO DESIRE TO COVER A $200 REPAIR ON A BRAND NEW BOAT WHEN A KNOWN ISSUE EXISTED. IT WASN'T THE DEALER--I WROTE THE LETTER DIRECTLY TO MERCURY.

SNYIRADY: For my pump conversion, I installed a relay on the main ignition switch, and an oil pressure interlock. Both parts came from Holley. Can you order these online and have them shipped? Everything has to be marine rated--I wouldn't recommend automotive parts in a bilge. As far as the oil pressure interlock, it's not a necessity, but a safety feature. If you're absolutely the only one who will be driving the boat, then you can probably get away with not installing it. Just make sure you realize that if the engine stops while the key is forward, you will continue to dump fuel into the carb (fire hazard). Another thing you can do is tie the electrical interlock into the alarm (if your boat has one). My boat alarms if it stalls. This is accomplished with another oil pressure switch I believe.

Here are the part numbers from Holley:
Order Details

Qty Product Number Description Cost
1 12-810 Fuel Pump Safety Pressure Switch $26.34
1 712-801-1 67 GPH "RED" Electric Fuel Pump $131.94
Shipping & Handling: $0.00
Sales Tax: $0.00
Total: $158.28


Unfortunately, I don't have any pics, and the boat is in winter storage. Nothing to really see anyway--just disconnect the old mechanical fuel pump. Find a machine shop who can make you a flange plate to cover the hole in the side of your engine (just give them the old fuel pump and have them make a blind flange to match the flange on the fuel pump (stainless so it doesn't corrode. Then run your fuel line to the new pump and wire it up! The install was fairly easy--and the engine performance was improved! Response time on acceleration is quicker. Just be sure everything is marine rated.

[Boston]

Sounds like your next move is to pull the fuel pump and check for wear on the arm. That and change your oil and look for filings on your magnetic plug. Something else I thought of that tends to make an annoying ticking sound is exhaust manifold leaks, but they tend to occur under load rather than at idle.

Anyway always check the simple stuff first. Mechanics will always aggrandize the problem but having turned all my own wrenches since the day I could pick one up, its not that way at all. Rarely is it anything major. Take your time, you'll figure it out.

Cheers
B