HPDI Exhaust Leak

[CStewart]

Anyone ever have an exhaust leak from the midsection of their HPDI? I noticed a noise last time on the water and when i looked back could tell there was exhaust coming up from the midsection.


I pulled the lower unit and check the tuner, and everything is good there. No melting or carbon deposits.

Haven't taken it to the shop yet, as I gotta use it tomorrow in a tournament, but had one gentlemen say it sounded like the upper mount may have come loose and knocked a hole in my exhaust plate. Never heard of that before, but with my luck it could happen.


any ideas?

[bhjr.]

I think there is a gasket at the top and a rubber boot like thing that seals the bottom. It's probably the rubber at the bottom, as the ones I've seen after some time get brittle and erode away.

[CStewart]

Well it held together for a 32 lb sack.


Gotta take it in I guess to get it looked at. This sucker sounds like one of those Mercury Racing Engines its so loud.

[Charlie206]

pictures, pictures, pictures. Great string.

[CStewart]

These were the best pics I could get of the tuner up inside the midsection

[Rich Z]

I don’t see anything unusual. Have you checked the rubber boot that is connected to the exhaust relief hole? Its just below the cowling pan on the back. Remove the cover plates and ensure the boot is connected to the exhaust relief.

[CStewart]

I'm trying to find that in the schematic in my manual

Is it under the cowling skirt or the midsection covers?

[Rich Z]

http://www.yamaha-motor.com/ou....aspx
#46

This is from an 05 250 hpdi under bottom cowling

[Charlie206]

You don't see any heat damage, melting or scorching on the water pump housing, correct?

[CStewart]

Water pump and lower unit look good. Seals are all in good shape

I am goin to pull the shirt to verify that boot again tomorrow. I remember seeing it last te I pulled the skirt bit I didn't know what it was or what it was for
I don't want to run it unless I get it fixed

[mullamaster]

Any news on this? I think I got the same problem

[hooken203]

Do you have water coming out where it shouldnt?
Possible blown gasket at the bottom of the power head where it seals to the mid section.

[CStewart]

I found the culprit this past weekend. I will try to post a couple of pictures I took later on tonight.


There is a square rubber boot/hose that comes up from the midesection to the top of the skirt that wasn't sealing. You couldn't see it till you pulled the midesection skirting and looked on the motor side of it. The lip that the compression ring squeezes was pushed in causing a exhaust leakage/excessive noise.

I pulled the bottom side and it too was pushed in, but not far enough for it to leak from there.

Quick easy fix, but definatly a pain to find. Thank goodness it wasn't anything actual with the power head.

[Rich Z]

Yep, that’s the boot I was trying to tell you about.

[CStewart]

Thanks for the Help as always Rich!

[CStewart]

Okay I lied.


The problem still isnt fixed. Went and really ran it this past weekend for the first time since I thought we got it fixed, and it still doing the same thing.

Runs great, but I don't want to keep running it, with it sounding like that. I guess I am going to have to break down and take it to the dealership. Anyone got any vasilene I can borrow?

[Rich Z]

HA HA, Inspect that boot again. Look for any visible marks where exhaust could be escaping before taking it to the dealer.