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BF50 Noise from valve train or??

S

Stillwater

New member
I have a 2004 BF50. It has a clicking/ticking noise which sounds like rocker arms. It is a constant clicking at camshaft speed.
Here's what I've done so far with no success. It is noisey enough I won't run it until I find the answer
-I have adjusted the valves (twice) to min spec .005 in. and .008 ex and the noise is still there.
-adjusted the camshaft belt
-The noise is in sequence to the valve train speed of 1/2 the flywheel speed.
-With a stethscope the noise is seems lower on the head and when put on the fuel pump it is very loud.
-I run the boat in the lake today to put it under load, but no change.
-At idle it's not too bad but audible and an increase in rpm brings a much luder noise Easily heard from steering wheel with cowling on
-throttle up in the lake from standstill to WOT is normal.
Two guesses on my part---
Has anyone experienced a fuel pump failure like this where the tension on the fuel pump plunger is weak and it makes a noise???
Has anyone experienced a "floating" rocker arm that slides a few thou on the shaft and snaps back against the spacer/spring assembly
I don't see evidence of a any wear/misalignment from a floating rocker arm.
Or am I missing something completely??
Thanks
(sorry for the long post but more info is better than not enough I guess)
 
So I answered my own question about the fuel pump. I was able to unbolt it and pull it out, plugged the hole with a rag, started the motor and pumped the fuel pump by hand and the noise was still there. So I'm getting real short on answers
 
You did not say that you took compression or did a leak down test.

Did you check any noise in your lower unit. One tooth off of the forward gear may cause the same effect. Sometimes the sound resonates up through the drive shaft and it could sound like it is coming from the engine. If it is suspect, you can pull the lower unit and start the engine for a short burst to see if the noise goes away.

One other place to check is under the flywheel. The magnets on some of the older 50's (not generally the 2004's) sometimes delaminate a little and the magnetics hit the coils under the flywheel. Generally, you can see some shavings accumulated on the pulser coils. The sound is a ticking at slow speeds and a whining that varies with speed at high speeds.

This is not looking for anything in particular, but pull the spark plug wires off one at a time to drop each cylinder and see if any of the cylinders drop differently. If the problem is internal, it might help isolate which cylinder is the problem.

Mike
 
Thanks for the reply Mike, I've done the compression and it's within tolerance. I did run it without lower unit and it's the same even running under load no load makes no difference. Hot cold no difference. I did check the flywheel and saw nothing.
I have wanted to run the engine without the valve cover on but was losing too much oil when I tried. Today I made up a milk jug partial valve cover and by tilting the motor up to the top of the trim range I was able to run it and use my stethascope directly on the rocker arms. With the stethascope on # 2 intake rocker it nearly took my ears out. The other rocker arms sounded normal. The cam lobe for that valve has a flat spot where the rocker comes off it's highest lift and just before it would fully close. It also shows a wear mark at that point on the lobe as if being pounded, although very slight. I checked the rocker and valve for proper movement and it feels very normal without any tight spots or sticking. It must be bouncing over the flat spot and making that noise. I'm a little concerned with my diagnosis that much noise is coming from that small area but there seems to be no better choice. Looking at the cam in general it has to be one of the worst grinds I've ever seen. I would not pay for a cam grind that bad. Has any one heard of camshaft issues with the BF50s or Honda in general?
Thanks
 
One other thought...have you checked the timing? Could a piston be hitting the valve?

Looks like it may be time to pull the head and see what the cylinder side looks like.

I have not see cam issues with any of the Hondas that I have seen. Others may have seen issues. Hopefully, they will jump in here.

The 40's and 50's have been around since the mid 90's with very little change. They are real workhorses. Ther are used a lot around here on work boats and get treated like crap, but still keep working.

Mike
 
I haven't checked the timing. As far as hitting a piston are these engines "interference" engines or free wheeling. For the time it takes to take the head off and inspect it sounds like a good idea. My thoughts on a valve hitting a piston have been that it wouldn't just happen to one cylinder, no? If the timing belt had slipped then it should run like crap but it runs good , just noisey. It just occured to me as I type this that if I roll the engine over so the valve is wide open I should get a little more travel on the valve, enough to tell me if the piston and valve are colliding. I don't think the valve is floating either as it doesn't matter the speed it's running. I've never seen a valve float at idle unless the spring was broken. It's not and feels the same as the rest. I don't have a gauge to measure spring tension so I'm just guessing on that. I was thinking of making up a level bracket to go under the rocker arm to push down on the top of the valve. Make it 12" long and use a scale to see what force is required. Not scientific but I could measure/compare all the springs.
 
Yes, it is an interference engine. It does seem unusual that only one cylinder would be hitting the valve.

Just check the timing marks on the cam and flywheel. It will be pretty obvious. Should only take a minute as long as you have the flywheel cover off already.

Mike
 
hondadude said:
Yes, it is an interference engine. It does seem unusual that only one cylinder would be hitting the valve.

Just check the timing marks on the cam and flywheel. It will be pretty obvious. Should only take a minute as long as you have the flywheel cover off already.

Mike
Click to expand...

I checked the timing marks and they appear to be one notch off. I'm taking it in to the Honda marine dealer today to let them listen and get their opinion of the noise. They may have heard it before. Our dealer has been around for 30+ years and have put a lot of Honda, Suzuki and now Yamahas out their door. I'm still thinking flat spot on the back slope of the camshaft but can't explain why it didn't make a noise from the get go. I'll keep you posted. BTW the flat spot looks like it dip below profile in the original casting and was missed in the grinding.
 
I took it to the dealer and that was just a waste of time. They listened an said they didn't know what the noise was but agreed it sounded like dead center in the valve cover. They said to do any more they would have to start tearing it down to see what they could find but couldn't for a couple of weeks. I should have known better. After I got home and cooled down I went through it again. It is at the #2 intake rocker. As I roll the motor over very slowly and watched with a magnifying glass as the rocker arm pad comes off the peak of the camshaft lobe it transitions from the heal of the rocker pad to the toe. Just before the toe makes contact it hits a little flat spot on the lobe and then when the toe hits it actually gives a little bump. I was having trouble understanding how the cam lobe and rocker arm could make such a noise until I saw the transition from heal to toe of the rocker arm pad. I don't have a dial indicator but I'm sure you would see a reading as the rocker arm slides down the back of the cam lobe and then bumps. Anyone understand what I'm trying to say here?? As for expensive I don't think it will be too bad maybe 400.00 marine bucks
Two further questions
1.When I align the timing marks I cannot get both crank and cam marks lined up together. one or the other is off about 1/2 a tooth. Not knowing the hours on the engine is that telling me I need a new belt or is that normal.
2. To remove the camshaft do I need to pull the head. It looks lie they have very thoughtfully put one oil pump bolt from the bottom up into the bottom rocker arm shaft casting with no way to access other than to pull the head
As always
Thanks for your help
 
OK, so answering my own question again. I took the head off which looks like it had to be done anyway. The oil pump bolts are not accessable without the head off. What I found once I got the rocker arms off was the pad on the follower for #2 intake had actually a worn low spot in the middle so not only did the cam show a flat spot but there was a divot in the follower pad that I could not see with it installed. Some of the other followers don't look good so I'll replace all rocker arms and cam. It gives a sense of relief that "ahah" that's what the problem is for sure but also it concerns me of why it would happen. Two things come to mind, the previous owner ran it low on oil or didn't service it very well. Camshafts are usually the first to suffer when that happens.
I still would like some input on the timing belt not aligning with both marks
Thanks again.
 
FYI Follow up on valve train noise, I took the cam and rocker arms into an engine builder who has been around here for at least 30 years and asked him what his opinion was of the cam and rockers I described in post #11. I was concerned about replacing the cam and not know for sure what had caused the wear and if maybe the cam and valve train where not getting lubed properly. He said there was no evidence of it not getting lubed as the cam journals where in perfect condition and that in his opinion whoever had owned it previously had either set the lifters with way too much gap or had never adjusted them at all depending on the hours on the motor. He felt they had simply self destructed. That for me wasn't something I had thought of but once he pointed it out it makes sense. He said with a cam ground with a transition ramp on the front and rear of the lobe the rocker arm gap is critical.
I am fairly fortunate. I only bought the motor recently and the guy I bought it from insisted that it was an excellent motor. I test run it and it seemed fine but on the water it was a different story. I called the guy on it and he has gone good for the parts and I said I would do the labor.
 
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