Mercruiser Riser Shutters???
JDavis1277
shutters (?) out the exhaust. BTW, its a 1978 model. My local Mercruiser
dealer said he can get replacements but advised me to leave them out. He said
the newer models do not have them.
After trying to remove the risers and having absolutly no luck, I'm inclined to
agree with him. Will TNT work to get these off or do you need a small nuclear
device????
Dave Brown, what is your opinion on this?
Anyone else have any experience with this problem?
TIA, Butch Davis-
LEngelb195
bottom of the Y pipe where it bolts to the transom assembly just on the inside
of the transom. Your dealer is wrong, the new models do have the flappers. They
are just farther up the Y pipe ... just below the rubber sleeve that connects
the intermediate exhaust elbow to the Y pipe.
The flappers help prevent water from coming back into the ehaust system and
ultimately into the engine when the engine is not running or running at very
low RPM. The water is most prone to coming in when launching the boat, when the
boat is beached and waves are hitting the transom, when the boat is stopped and
everyone rushes to the back to see the big fish being landed etc.
Are they needed? Do you think that manufacturers would spend the money and put
them in if they weren't?
Marshfield Mass.
The exhaust shutters have a very important job to do. They prevent
water from coming up exhaust into the engine during rapid
deceleration or in a following sea.
The exhaust shutters on your 1978 Mercruiser are located at the
bottom of the 3 piece Y pipe. Later models have the exhaust shutters
at the top of the Y pipe. You'll need to remove the engine to get at
it. Replace the Y pipe seals while replacing shutters. While the
engine is out see if the oil pan is rusted enough for replacement.
Also look at the engine coupler. If the splines are worn, replace
it. Throw in a new set of rear engine mounts while you're at it.
Don't forget to check engine allignment when you are finished. You
should also give serious consideration to replacing the risers.
--
Jim Clark
Custom Yacht Services
Marshfield, Massachusetts
(EMAIL) custom-yac...@worldnet.att.net
(WEB PAGE) http://home.att.net/~custom-yacht-services
JDavis1277 wrote in message
<19981106084114...@ng84.aol.com>...
Dave Brown
> While running my FWC 260 Mercruiser yesterday it spit the backflow preventer
> shutters (?) out the exhaust. BTW, its a 1978 model. My local Mercruiser
> dealer said he can get replacements but advised me to leave them out. He said
> the newer models do not have them.
My first question is why they spit out? Did you recently overheat?
> After trying to remove the risers and having absolutly no luck, I'm inclined to
> agree with him. Will TNT work to get these off or do you need a small nuclear
> device???? Dave Brown, what is your opinion on this?
Install new ones. They keep water out on rapid deceleration, and when parked stern
to the wind.
--
Regards,
Dave Brown
Brown's Marina
http://www.brownsmarina.on.ca/
zigzag
are they?
I believe my exhausts both collect at the top rear of the engines, then
flow back to the transom, where they are exhausted down through the
bottom of the hull (one on each side). Don't see where they would be or
why they would be necessary on I/O's but not Inboards.
Bill McKee
zigzag wrote:
It has to do with all the engines inside the boat. The difference
between an I/O and a pure Inboard is the connection to the prop. Actually
the Inboard may be more at risk of ingesting water as they may sit lower in
the hull in relation to the water line. Most tournament ski boats I see
have the rubber flappers on the exhaust outlet at the transom. My Jetcraft
is this way. Any boat that can have the following wave hit the back of the
boat as you slow down can have that wave push the water up the unprotected
exhaust hose / pipe. There is a lot of pressure exerted on the back of the
boat by that wave hitting hit, as well as waves hitting the transom as you
are tied to a dock or launching.
Bill
JDavis1277
Thank you, and all the others who took the time and trouble to respond to this
post.
Yes, I had an overheating condition. After 4 plus years of sitting I have been
working on getting my boat back in the water.
I had connected a "Fak-a-lake" (?) to the hull intake for the raw water pump
and the dual suction cup thingies to the outdrive intake. Both are hooked up
to the garden hoses for out of the water cooling.
When I finally got the engine to smooth out a little yesterday I noticed the
temp was climbing faster than I expected. I shut the engine off, but noticed a
burning rubber smell. When I dismounted the boat I found the rubber coated
steel parts below the lower unit. There were three pieces, looked like half
ovals. I assume there are 4 pieces and that 1 remains in the engine or the Y
pipe somewhere.
After the engine cooled down, I removed the hose from the power steering fluid
cooler and found a piece of the raw water impeller (Barco). I assume the
impeller, at a minimum, is shot and plan to replace it as soon as I can get
another.
I have learned that I should have inspected the impeller before starting the
engine after a 4 year layup. But, I was in a hurry and too lazy. Oh well, I
didn't have time to do it right, so I'll have to find time to do it over and
the money to correct any damage I've done. At my age (58) and as long as I
have had this boat (20 years), you'd think I would have already learned this
hard lesson.
Thanks again, Butch Davis-
Bryon Kass
off
or replace the risers and manifold assemblies. I would not suggest torch
cutting if the engine is in the boat. If that engine is completely raw
water
cooled you should think of repowering.
Bryon Kass
webmaster and
Custom Design
150 Mechanic St.
Foxboro, MA 02035
508-543-9068 or fax 508-543-5127, Foot yard 508-384-2415
in THE ENGINE ROOM http://home.ici.net/~cusdn
JDavis1277 wrote:
>
> While running my FWC 260 Mercruiser yesterday it spit the backflow preventer
> shutters (?) out the exhaust. BTW, its a 1978 model. My local Mercruiser
> dealer said he can get replacements but advised me to leave them out. He said
> the newer models do not have them.
>
> After trying to remove the risers and having absolutly no luck, I'm inclined to
> agree with him. Will TNT work to get these off or do you need a small nuclear
> device????
>
> Dave Brown, what is your opinion on this?
>
H82LOOSE1
/ can be a problem, but there is another problem called reversion that you
should be just as concerned with. It may not be as much of a problem with the
small block motors as it is with the big blocks.
Either way, get it fixed.
Mike G.