1998 115 reed/intake noise VIDEO ADDED

[jeremy5780]

I just rebuilt my 115 crossflow and it is sitting on my work bench! I have the carbs off and was turning the crank to check for binding ect ect and it turns smooth. However it is making a noise out of the top left intake hole like a backfire would sound like. if I put the palm of my hand over that hole while i turn the crank it has a strong sunction then it blows air out. Also when it makes this noise I can see the reed valve move. On the other three intake holes the reeds do NOT move they do NOT make noise and there is no suction or blowing when I hold my palm over the hole, and turn the crank. Anythought?

 

[oldcatamount]

Re: 1998 115 reed/intake noise

Re: 1998 115 reed/intake noise

When you re-built the motor, did you have the cylinders re-bored or honed? The reason I'm asking is that if a cylinder wall isn't honed correctly, the crankcast pressure (vacume) will be screwed up and cause the symptoms you are describing.

 

[jeremy5780]

Re: 1998 115 reed/intake noise (VIDEO ADDED)

Re: 1998 115 reed/intake noise (VIDEO ADDED)

yes honed out by a marine engine shop and new piston rings added! Also they are carbon fiber reeds.And the plugs are out. I'm attaching a video I just took, where you can hear the sound coming from the top left intake hole. http://s199.photobucket.com/albums/aa162/jeremy5780/?action=view&current=motor037.mp4.

If you click the link you should get the video THANKS IN ADVANCE

 

[oldcatamount]

Re: 1998 115 reed/intake noise (VIDEO ADDED)

Re: 1998 115 reed/intake noise (VIDEO ADDED)

Interesting video. I could hear the "suction" sound clearly. Another question for ya, did you re-install the pistons after the hone, or did the machinist do it? Reason for asking, the crossflow pistons need to be installed with the sharp side slope toward the intake side of the crankcase but, don't tear the motor apart on my say so here, because I'm relying on my old memory.

 

[jeremy5780]

Re: 1998 115 reed/intake noise (VIDEO ADDED)

Re: 1998 115 reed/intake noise (VIDEO ADDED)

yes your correct I installed them and they are the sharp side to the intake. I made sure of that. It is definatly the reed making the noise if I stick my finger in there and hold the reed plate open the sound stops. It's like a snapping sound of the reed plate opening. Keep in mind there are still a few hole in the intake not sealed such as the starter holes as well as the fuel pump holes. As well as the carbs. I just dont want to put all this back together then have to tear it back apart. Also another concern is that this reed is going to break and then I have to tear it back down!

 

[oldcatamount]

Re: 1998 115 reed/intake noise (VIDEO ADDED)

Re: 1998 115 reed/intake noise (VIDEO ADDED)

Breaking a reed is very hard to do. It almost needs to be deliberate. I didn't realize that you weren't finished with fuel pump etc. My suggestion is to put it back together as is. If you need to re-address the reeds, it's not a complete tear down to do so. I totally understand your hesitance here. It's a lot of work and money to do things twice, espeacially with a motor of that value.

 

[jeremy5780]

Re: 1998 115 reed/intake noise (VIDEO ADDED)

Re: 1998 115 reed/intake noise (VIDEO ADDED)

thanks anyone else??????????????????