1999 MXZ 500 - RPM / Too loud - Snowmobile Forum: Your #1 Snowmobile Forum

iAndrew · 02-20-2013, 12:37 PM

Hey everyone,
I'm new here and I'm new to the snowmobile world. I just picked up my sled two weeks ago and I'm loving it. Great condition, new studs, brand new seat, no cracks. Runs great.

This past weekend I have noticed something wrong when I was accelerating at 30 mph and the engine got louder with a higher pitch and the rpms went up by 1 and 1/2 more than it should.

I turned off the sled thinking it was over heating but noticed nothing strange. Just runs louder and I feel like I didn't have much power.

The exhaust sounds way too loud than its ever been.

Any ideas as to what the problem could be?

I'm running a 1999 Ski Doo MXZ 500.

Thanks,
Andrew

joshkidner · 02-20-2013, 01:12 PM

maybe it is running too lean? I think it would help more if you took a video of what you are talking about so we can hear what you are hearing. goodluck on fixing it though!

rgoers · 02-20-2013, 01:32 PM

A '99 sled... in MI... based on my experience in the NE US, rust happens.

I'd take a look at the pipe and the y-pipe in particular. Any holes that may have rusted through would increase the noise and decrease power.

**smallengineguy** · 02-21-2013, 03:40 AM

Replaced the belt yet?

iAndrew · 02-22-2013, 08:09 AM

Brand new belt.

I got a report back from the local shop near Traverse City and they noticed a few things wrong near the engine. After he replaced the brake switch I asked him to find out where the loud noise was coming from. Apparently the exhaust shield wasn't secured.

1. The manifold only had 3 bolts left. There should be 8.

2. Two of the gaskets are shot, replacing those which you can only get from Ski Doo. They apparently don't make aftermarket version.

That's all I know for now, I should hear more from the shop Tuesday or Wednesday. Has the gaskets on order.

rgoers · 02-22-2013, 08:34 AM

Well, at least I was pointing you in the right direction... seems like it *was* an exhaust leak... just not a rust hole, like I was guessing it was.

iAndrew · 02-22-2013, 08:46 AM

I'm happy it's being taken care of now and not having more problems down the road.

**smallengineguy** · 02-22-2013, 06:45 PM

Cheap parts too!

iAndrew · 02-23-2013, 12:37 PM

They are going to make sure the Y pipe isn't warped too considering who knows how long it's been hanging on by two bolts and with that cold air coming in.

So with all these problems which are being fixed as we speak, was this affecting my sled's performance at all? Do missing bolts on manifolds and two bad gaskets make a decrease on the snowmobiles performance or speed?

**smallengineguy** · 02-24-2013, 06:38 AM

Yes it will slightly. The engines need back pressure from the exhaust to perform correctly. You were losing that through the leak.

iAndrew · 03-06-2013, 06:08 PM

Alright, so another problem came up to their attention while removing the exhaust.

- Motor Mount, which is currently discontinued by Ski Doo themselves.

So they took off the mount, and sent it next door to their Welding Shop and in a day turn around they were able to reinstall it with no issues. Apparently it was broken in half, only leaving three left holding the engine.

I am also having them replace the linkages, bell-crank/ bushing and collar to tighten up the steering. There was a lot of slack/slop in the steering which made it difficult for me at high speeds.

I will let you all know how the sled turns out tomorrow.

**BC_Dan** · 03-06-2013, 07:33 PM

Motor mounts breaking are pretty common in all sleds, I've had a few over the years. Most of them are rubber between two bolts and the rubber breaks. The rubber acts to dampen vibration, but is a lot easier to break.