Suzuki DT 4 - Crazy Noise

[Chris Arias]

Hi. I just bought a sailboat with an '87 Suzuki DT4 outboard. After not being able to start it, I removed the carburetor and found the float bowl fouled with gobs of emulsified crud. Got it all cleaned out and it started on the first pull.

I submerged the lower unit and let it run a while. It seemed to be doing great. It wanted to stay on half-choke for some reason. It was 45 degrees out, so I figured between the cold and years of non-use were the reason. I finally turned the choke off and kept the throttle to the same setting as half-choke. It revved up a little and seemed to be doing great. Then after 2 solid minutes, it started making this horrific rattle. I killed it immediately. Tried again a half hour later with the exact same results.

It almost sounds like a bad bearing somewhere in the flywheel assembly. Defeinitely sounds like a power unit issue. Could it be the water pump? It pees okay. Not a forceful stream, but a consistent, healthy enough looking dribble.

Your thoughts?

Thanks!

 

[drewmitch44]

Re: Suzuki DT 4 - Crazy Noise

Does it pee ok or does it dribble? Can you tell when you were running it where the noise was coming from as far as upper or lower. Most likely not the water pump making the noise. And did you say that you were running it out of the water then put it into water? Just wondering cause overheating can cause everything in the world to go wrong. Running out of water can cause the sky to fall and and bowling ball sized hail to rain down on your head. Im just saying that if you run the motor out of water you can cause serious damage that can be almost anything.

 

[Chris Arias]

Re: Suzuki DT 4 - Crazy Noise

Thanks for the reply. I'm guessing water pump too. I got a manual today and will tear into it tonight. As far as running out of the water, I only ran it dry for about 30 seconds. The test I wrote about at length was all with the lower unit in a bucket of water. Could crud in the water be messing things up? I'll start with clean water again tonight.

If the water pump gets noisy, does that necessarily mean it's shot, or just needs some TLC? To answer your question, it seems to dribble, not pee a healthy stream like my Merc.

Thanks again!

chris

 

[Chris Arias]

Re: Suzuki DT 4 - Crazy Noise

Okay...The sound seems to be coming from directly under the flywheel. Has me a little scared that it's something major. It sounds awful and it definitely puts a drag on the motor. I always cut if off immediately. Funny thing is, I can kill it and restart it and it still takes a minute for it to start making the racket again.

Things that make you go, "Hmmmm..."

chris

 

[gotboostedvr6]

Re: Suzuki DT 4 - Crazy Noise

Well you eather ran it lean and overheated, ran it with no water pressure and overheated, or didnt use enough oil causing overheat. in any case the cyl walls are scratched, the pistons are prob melted, and the bearings chewed themselves to death..

 

[rodbolt]

Re: Suzuki DT 4 - Crazy Noise

as you say you just bought it it may have had water damage to the crank/needle bearing assy?s before you got it.
the fact it had crud in the carbs indicates serious neglect.
check the lower unit oil for metal, the water pump is still a rubber impeller so it wont make noise even if the vanes are missing.
coild be something as simple as a loose coil under the flywheel to a main,rod or wristping bearing failed.
if the carb had water in it odds are very high the crankcase did as well. the shiny parts of the crank and rod assy?s dont tolerate water well at all
what oil ratio did you mix your fuel with ?

 

[Chris Arias]

Re: Suzuki DT 4 - Crazy Noise

Okay...So I bought a maunaul, but it didn't cover the 1993 model.

I started to remove the lower unit and didn't realize until then that it's attached to the clutch rod at the top. Can I remove the power head as a complete unit by removing the six screws on the underside of the powerhead?

I drained the lower unit oil and it was nasty. No metal, but seriously green and sludgy. I think the motor was neglected for quite some time, so I may be in for more than a water pump. What else should I plan to address?

Thanks for all your help.

 

[Jay Mize]

Re: Suzuki DT 4 - Crazy Noise

Chris
Did you ever figure out what the wierd noise was coming from? My DT4 has the same noise. Strange vibration . whirring when you rev it up.

 

[Doug C]

Re: Suzuki DT 4 - Crazy Noise

Had a noise in a Suzuki DT4 that sounds like that described.
Discovered that the rubber bushing about half way up the driveshaft had dropped down. The driveshaft had a mark where it had rubbed against the lower leg casting where it passes through a hole.
I can only assume that the driveshaft starts vibrating and flexing at certain engine speed, causing the horrendous noise.

Douglas

 

[Sandy_Milliken]

Re: Suzuki DT 4 - Crazy Noise

I picked up a 95 DT 4 last summer. Had the noise occasionally in high revs (near WOT) in neutral. Didn't happen the couple of times I used it in the water in gear. Noise was definitely in the top end (power head) and not at the water pump.