Outboard "rattles" at high RPM and it didn't used

T

timflan

New member
What the what?!

My Suzuki-manufactured 2004/5 Johnson 90 (EFI, 4-stroke) outboard started "rattling" or "clicking" at high RPMs. First time I noticed it was in October 2010, and today when I ran back and forth in the speed testing lane on Seattle's Lake Union, I got exactly the same thing.

Engine started fine, ran fine, despite sitting for a few months. But at WOT and a bit below...clickety-clickety-clickety.

So what gives? Something with valves or cams, right?

Thanks!
 
The experts will be here soon, but for starters, how about detonation? How old is the gas and was it "good" when you got it?

Carbon deposits do build up over time, which can cause detonation. Just the first thing that came to mind. Or check the oil to see if you have any.

Boris
 
I own Yamahas, but the first thing I'd do is remove the outboard cover, then remove the flywheel cover and look for something obvious, maybe loose. If nothing obvious up top, check for chips or bends on the prop. Other than that, possibly something more serious internally.
 
It's got oil. And although it's been a year since I serviced the engine, I've only put about 50 hours on it. I was going to skip this year's service since the engine has been used so lightly the past year.

The gasoline...is easily over six months old at this point. Possibly eight months, but not more than that.

I did "bump" bottom with the outboard literally the day before I noticed the new rattling in October. I was barely moving, exploring the Sammamish River as far upstream as I could get. Me and the kayakers, pretty much. Sounder was flashing, meaning I was in shallower water than it could measure, and I was idling in forward, watching the bottom through the side window. When she touched, I killed the engine, raised the motor, and let the current push me back downstream into deeper water. There is no apparent damage from this event, but the fact that I first noticed the rattling on my way home from that adventure...In the immortal words of Led Zeppelin, "It makes me wonder..."
 
Sent Larry H. a PM. He'll chime in if he's around. Sounds to me like when you hit bottom, you may have bent something inside the engine. That's not good. :cry

Charlie
 
That year Johnson is a Suzuki in white paint. I would call the Suzuki dealer for any advice they might have. If the prop hit something in the river, you might have damaged a gear, but at idle I think that is unlikely. Did the motor stop running when you hit bottom? Is there any damage on the prop?

If the lower end is OK, that leaves the powerhead. Valves can make a sound as well as rod or main bearings. Detonation or 'pinging' makes a rattling sound.

I would eliminate the fuel as a suspect by running on known-good new fuel. Detonation from low octane is possible. Most of us have heard 'pinging' in cars or trucks due to low octane or too much spark advance. The new cars adjust themselves to eliminate pinging.

The first and easiest thing to do is test on new fuel. Perhaps you could get new fuel in your kicker tank and run on that to test.
 
The engine did not stall. I don't think the prop made any contact at all.

Yes it sounds a lot like "pinging" I remember from cars in the olden days.

I'll try the fuel first.

Thanks!
 
Tim,

Did the fuel have Marine Stabil in it for that "six months plus" fuel storage? I hope so. If not I would start adding it, and Startron fuel treatment, and fid a way (kicker tank) to run that fuel through with about half new gas. If it is the pinging, and it is that predetonation thing maybe the new gas will help.

By the way, When, (day & times) are you (your group) playing at Friday Harbor?

Thanks and good luck.

Harvey
SleepyC :moon
 
I don't add any fuel-preservation additives, because NORMALLY I run the boat enough to use up the fuel. This past year has been a real challenge for me, professionally and emotionally. Plus the weather has sucked, mostly. As a result, the boat hasn't gotten much use over the winter. Right now both tanks are about half full. What I think I'll do is siphon the fuel from one tank into the other tank and fill the now-empty tank with new fuel, and then run it.

If it turns out the fuel is to blame, then I'll run off the "good" tank and fill it about 1/4 with "bad" fuel with each fill-up until it's gone. Sound about right?

Alas...no Friday Harbor for us this year, and we are ALL BUMMED OUT about it. It's my family's favorite C-Brats event, and we're sorry to miss it. Arwen has first communion that weekend, however, and apparently this is some sort of Big Deal to Catholics. :-)
 
"Alas...no Friday Harbor for us this year, and we are ALL BUMMED OUT about it. It's my family's favorite C-Brats event, and we're sorry to miss it. Arwen has first communion that weekend, however, and apparently this is some sort of Big Deal to Catholics."
Click to expand...

Oh Yes, I remember now from the FH thread, but you are going to be there on July 4, Is that right? Looking forward to it.

Sounds like a good plan, with the gas, That should be a good mix. Sorry it has been a tough year. I think I can understand, been that way here too. I would recommend the Blue Stabil at least, in every tankful. I think it is good insurance.

Harvey
SleepyC :moon
 
I too would suggest starting with the gas. Start with the easy stuff...

Bump is relative - from what you described it would not sound like a damaging bump if you just touched your skeg. You mentioned the sound of old cars...like when you step on the gas and hear rattling? The engine pros should be able to help - rocker arms or valves out of adjustment?
 
We recomend Sta Bil be used all the time, just in case. It helps with ethonal problems and helps retain Octane level in the fuel. Today's gas goes bad very quickly.

I'm guessing fuel is the root cause of the problem.
 
I concur with Matt, I've run stabil year round and had no issues, modern gas goes stale over lunch. Get out there and burn it off, right about 4 gallons an hour seems right, 4100 rpm 15 knots 1 c dory grin. George
 
OK, I haven't had a chance to give this much attention, but today I ran the engine, I switched between the two fuel tanks and ran it at a variety of throttle settings. I heard the rattling when I ran it above about 3000 rpm, but not at lower RPMs.

But now I think I have new, helpful data. Video data:
Tim's YouTube video

Now I could'a SWORN I checked the rotation of the prop in neutral, with the engine off, right after I got unstuck when I was up the river last fall. It's the first thing I do after running into debris or touching bottom. Check the prop, examine all the blades, make sure it turns freely and on-axis.

It's virtually impossible to imagine that I did NOT do this back in October. So what happened? Perhaps I was simply not looking for a clicking sound. My focus would have been on the prop, the rotation, and the ease of movement. Maybe I just didn't notice the clicking.

Or maybe it's something that's gotten worse since then?

I just don't know. Experts, please watch my little video and tell me what you think. Thanks!
 
i would have to come see it, and I can tomorrow afternoon if lunch is involed. I could not see if the prop was striking the vinc finn but it sounded like it. or....some thing is between the prop and the gear case Or.... something in the gear case is loose. i would pull the prop off and inspect it. do you have a dinghy?
 
starcrafttom":al72jo3j said:
i would have to come see it, and I can tomorrow afternoon if lunch is involed. [...] i would pull the prop off and inspect it. do you have a dinghy?
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Lunch will be provided. Have dinghy, but probably easier to find a spot where we can back the boat up against a dock.
 
I have to supervise a marine survey in the morning in la Conner but should be in Seattle around 1pm? I will give you a call when I leave la Conner. Wheres the boat at? and email me your number encase I don't have it.
 
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