OMC Through The Prop Exhaust

[imported_Gary L]

I recently bought a 1980 Century Arabian 200 with a 350 Chevy and OMC 800 stringer, low profile, mechanical shift drive. I am having fun replacing the water pump drive shafts and ball gears but the exhaust system looks like a bad setup to me. I don't see how the 350 can possibly breathe through that system let alone the heat that has to be generated in the drive. Is my concern justified? Is there any reason I can't swap the manifolds side to side and plumb up a through the transom exhaust with stainless steel exhaust pipe? Would it be worth the effort? Does the present systen have an anti backwash flapper? I don't see one. Would I need one with the through the transom modification. This is my first stern drive and I read the posts every day. I have learned a lot and appreciate the information available. Thanks a bunch. Gary L

 

[Boomyal]

Re: OMC Through The Prop Exhaust

No doubt outdrives restrict exhaust. But they are oviously suffecient for the low rpm marine motors. There are no flapper that I am aware of.

And yes you can run thru the transom exhaust. You'd just have to cap off the exhaust ports on the intermediate housing.

One of the reasons that you do not want to run your motor without water is because you will cook your shift cable running down thru the exhaust port. Otherwise they stay cool enough with the water stream going thru it.

 

[imported_Gary L]

Re: OMC Through The Prop Exhaust

No doubt outdrives restrict exhaust. But they are oviously suffecient for the low rpm marine motors. There are no flapper that I am aware of.

And yes you can run thru the transom exhaust. You'd just have to cap off the exhaust ports on the intermediate housing.

One of the reasons that you do not want to run your motor without water is because you will cook your shift cable running down thru the exhaust port. Otherwise they stay cool enough with the water stream going thru it.

 

[imported_Gary L]

Re: OMC Through The Prop Exhaust

OK, thanks Boomyal. If it has run ok for 25 years I suppose it still will. It's just that I'm used to putting headers and dual exhaust on small block Chevys to get them to run. Gary

 

[KaGee]

Re: OMC Through The Prop Exhaust

BTW... the "flappers" are in the bellhousing.