Suzuki DF175 rattling noise

[Eastcoastfloyd]

Hello I have a 2010 Suzuki DF175 with 1100 hours on it. Motor runs great but when accelerating it makes a decently loud rattling noise. I have no codes or any other running issues. I have attached a link for a video. I was thinking timing chain tension or something in the balancer but I’m not sure. It doesn’t not make the noise at idle or any other time just under load when accelerating.

[Eastcoastfloyd]

Nothing? Spark knock?

[redlowrey]

I can't distinguish the rattle over the engine noise, but I can hear something that is not right, three things are common with the DF175, timing and balance chain, and the butterfly assembly plate inside the inlet manifold which controls the air flow, the plates are plastic and break up and end up in the combustion chamber.
That is what it sounds like to me, do your self a favor and take your boat to someone that knows what they are doing or you are going to end up in a world of hurt.

[Eastcoastfloyd]

So if the butterfly assembly plastic plates broke and ended up in the engine we would have an engine that did not idle or run correctly at all right?

[Moonlighter]

So if the butterfly assembly plastic plates broke and ended up in the engine we would have an engine that did not idle or run correctly at all right?

It can do far worse than make it run badly! Any hard object entering a combustion chamber or the intake system is not good!!

Honestly, and I am trying to be kind here, but even asking such a question says that you really should take Red’s advice and take the motor to someone who has well proven knowledge and experience in working on Suzuki 4 strokes and get them to check it over thoroughly. Mechanics that dont work on Suzukis regularly may not be aware of the things to check.

Ask friends in your area if they can recommend a good Suzuki dealer in your area. Finding a experienced Suzuki tech in your area that you can trust is very important.

By all means, show them the video and also let them know that you are aware of timing chain and butterfly issues affecting these motors and that you want them checked.

[redlowrey]

So if the butterfly assembly plastic plates broke and ended up in the engine we would have an engine that did not idle or run correctly at all right?

What it means, if the rattle is from the plastic butterflies and a piece gets jammed under the inlet valve, the valve will stay open and the piston will strike it, asta lavista baby.
The noise may have nothing to do with the manifold, just get it checked.
When the engine is running at low speed the butterflies will be in the closed position tight against the housing, short runner, at high speed no manifold vacuum the spring on the control rod will pull open
the butterflies and they will be able to rattle on the shaft.

[Eastcoastfloyd]

Yes I understand and know the answer to the question. Like I said the engine runs perfect so the intake has not come apart but I will pull it and check it. I was simply asking for opinions on what a noise like that could be from. One Suzuki dealer said it was spark knock and to put new gas in it and it will be fine and one said it was the balancer chain. I figured I would get the standard answer “bring it to your Suzuki dealer”

[Handsomerob1980]

Sounds like Prop knock, google some videos of it.

[Badesmelb]

Did you sort it out . I have a similar issue on a new install wondering what the outcome was ?