Volvo AQ151C has ticking noise when at idle (video link)

[fishalope]

I just had my AQ131 replaced with a AQ151C. At idle, there is a fairly loud ticking noise that goes away when power is applied. Here is a short video with sound that I took of the noise. I have it paired to a SP-A outdrive if that helps. Also when I took it out to test it on water, It loses power and backfires at around 2-3000 rpm's. Above that it runs great albeit WOT is only at 4400 RPM. In addition, the temperature on the guage shows 200-210 degrees. Thank you in advance.

http://vimeo.com/21263188

 

[BossHogg]

Re: Volvo AQ151C has ticking noise when at idle (video link)

Just bumping back up to the top for you. I don't know much about boating. I dont know anything about Volvo motors. However, I do know car engines. If I had to take a stab it sounds like a lifter. It could also be a broken valve spring but I wouldn't expect the noise to go away past idle if that were the case. I bet lifter.

 

[Black as]

Re: Volvo AQ151C has ticking noise when at idle (video link)

If you have broken a valve spring the motor would be running rough.

I would start with an oil and filter change and see if the ticking goes away, if it doesn't you will have to start digging a little deeper eg; oil pressure, valve spring, lifters etc

What you could also do is add engine oil flush, it cleans the inside of your engine and helps with sticky lifters etc, run that in your engine for about 15 minutes as per the instructions on the bottle and then drain your oil

Some will have there point of view about doing this but has done me fine over the years

 

[Don S]

Re: Volvo AQ151C has ticking noise when at idle (video link)

I would get a mechanics stethoscope and see if you could isolate where it's coming from. Even when you give it throttle, it sounds terrible.
Also do a compression test.

 

[fishalope]

Re: Volvo AQ151C has ticking noise when at idle (video link)

I would get a mechanics stethoscope and see if you could isolate where it's coming from. Even when you give it throttle, it sounds terrible.
Also do a compression test.

I will do that today. Thanks Don

 

[Silvertip]

Re: Volvo AQ151C has ticking noise when at idle (video link)

The noise seemed to increase as the mic was moved to the forward end of the engine. That would seem to indicate a timing gear issue -- especially since it decreases with a bit of throttle. Slop in the system at idle is taken up with added throttle. This was a common problem on some high-time Buick 3.8 V6 engines. In those engines timing chain wear and the plastic coating on the timing gear would cause that same exact noise because the chain would smack the side of the front cover. This isn't happening on your engine but timing gear slop would create the noise you hear. You can check that slop by rocking the crank pulley back and forth and listen very carefully for the tell tale click as the slop comes out of the system. Removing the valve cover can help determine just how much slop there is. DO NOT rotate the engine backwards -- you are simply interested in determining how much slop there is. Otherwise Don's suggestion about using a stethoscope would help. If you have a broom handle or a piece of plastic pipe or even a short length of garden hose makes a good stethoscope. Go along the valve cover listening carefully for the clicking. Move to the front cover to listen to timing gear noise. If this engine has a block mounted mechanical fuel pump don't overlook it. By all means "diagnose". Do not start throwing parts at it and hoping for a solution.

 

[Don S]

Re: Volvo AQ151C has ticking noise when at idle (video link)

He doesn't have any timing gears. It's a Volvo 4 cylinder with a timing belt. All visible.

 

[fishalope]

Re: Volvo AQ151C has ticking noise when at idle (video link)

I used a stethoscope and the ticking seemed to be coming from the front 2 cylinders at the top. I then did the compression test from back (stern) to front and the results were 115,110,85,and 95. Hope this helps. Thanks in advance for your wisdom in such things.

 

[Don S]

Re: Volvo AQ151C has ticking noise when at idle (video link)

If your gauge is right and you did the compression test properly, you have a serious engine problem. 142?170 psi is where your compression should be. Have you checked your oil lately? Did it by any chance seem real thin and smell like gas?

 

[fishalope]

Re: Volvo AQ151C has ticking noise when at idle (video link)

I had my friend who is a Volvo automotive tech do the compression test and he thought the valves may be out of adjustment. He also said he only works on cars so he doesn't know if the marine version is different. I just checked the oil and it is at the proper level and smells like oil and is not thin.

 

[fishalope]

Re: Volvo AQ151C has ticking noise when at idle (video link)

I purchased the engine from a local marine mechanic who had the engine sitting in his shop for the last 6 years with plans of repowering one of his boats. It came from Lake Tahoe originally. He did tell me that he was under the assumption that it had hydraulic lifters and therefore did not adjust the valves after the installation. When he removed the AQ131 from my boat to replace it with the AQ151, I had asked him to fix the AQ131 that he took out. He told me that it only needed an oil pan and to check the bearings. If he was dishonest, he could have stuck it to me at that point. I believe him that it was running perfect on the stand before he installed it and it ran great after the installation on muffs. But I have been wrong before

 

[Don S]

Re: Volvo AQ151C has ticking noise when at idle (video link)

It doesn't have hydraulic lifters, it's an overhead cam. Here is a link to the OEM service manual you can download for free. Might want to do some reading about your engine.

http://www.4shared.com/file/64741910/25295432/230_250_251_131151171.html

 

[fishalope]

Re: Volvo AQ151C has ticking noise when at idle (video link)

Thanks for the link Don but I own the owners manual and the shop manual and the outdrive shop manual. I am fully aware that my engine does not have hydraulic lifters. I said that the mechanic who sold me the motor was not aware. I have read the manuals but most is over my head.

 

[fishalope]

Re: Volvo AQ151C has ticking noise when at idle (video link)

Don, Is it possible that when the valves are adjusted properly that some of my problems would be fixed?

 

[Don S]

Re: Volvo AQ151C has ticking noise when at idle (video link)

It's possible, did it ever run right since you have had it? It's not like they will go out of adjustment.

 

[fishalope]

Re: Volvo AQ151C has ticking noise when at idle (video link)

No, It ran like in the video since it was first started at my house after the install. Could it possibly be the timing belt is a tooth off?

 

[Don S]

Re: Volvo AQ151C has ticking noise when at idle (video link)

Trust me, if that belt is off one tooth, it won't start. Pull the valve cover and check the valves and let's see what you have.

 

[fishalope]

Re: Volvo AQ151C has ticking noise when at idle (video link)

I will have my Volvo guy adjust them to spec and see what happens. Crossing my fingers. I also laser temped the engine today and it was running at around 165-170 degrees. My temperature gauge must be reading hot. Thanks again!!

 

[fishalope]

Re: Volvo AQ151C has ticking noise when at idle (video link)

I checked the valve clearance and from the back of the boat to the front. They read as follows: 0.010-0.013-0.011-0.016-0.015-0.016-0.014-0.015 They were all checked when the engine was cold. They appear to be within close to within specs. As understand 0.0118-0.0157. I have not adjusted them yet.

 

[Don S]

Re: Volvo AQ151C has ticking noise when at idle (video link)

Check your idle speed and timing, also check the dwell. Post the results.
Also, redo the compression test and verify the gauge is correct.