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Riser elbow, 4.3?

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Mikey N.C.

Advanced Contributor
Customer's regal boat, he bought knowing motor was bad. Original 4.3 vortec
with batwing exhaust manifold's. Customer bought used pre vortec ( 12 bolt intake) motor in VA. . used motor has manifolds , with risers and no spacers.
I've already dropped in motor. And have 3 set's of the elbows that are angled back toward transom. Do I need riser spacers and 90 degree elbows?
Thanks
 
Mikey N.C. said:
Customer's regal boat, he bought knowing motor was bad. Original 4.3 vortec
with batwing exhaust manifold's. Customer bought used pre vortec ( 12 bolt intake) motor in VA. . used motor has manifolds , with risers and no spacers.
I've already dropped in motor. And have 3 set's of the elbows that are angled back toward transom. Do I need riser spacers and 90 degree elbows?
Thanks
Click to expand...

Ayuh,..... You need the riser blocks, only if the motor sits to low,.....

I believe the static water level has to be 14" below the exhaust turn inside the risers/ elbows,....
 
Mikey N.C. said:
Customer's regal boat, he bought knowing motor was bad. Original 4.3 vortec
with batwing exhaust manifold's. Customer bought used pre vortec ( 12 bolt intake) motor in VA. . used motor has manifolds , with risers and no spacers.
I've already dropped in motor. And have 3 set's of the elbows that are angled back toward transom. Do I need riser spacers and 90 degree elbows?
Thanks
Click to expand...
i think the 4.3 s use a different down elbow after the exhaust eblow on top of manifold or riser block, the v6 down elbows drop the exhaust farther forward than a v8 down elbow . I had to get different ones when swaping a 4.3 to a 5.0 maybe you have ones for a V8 ?

the v6 ones look like these https://www.ebay.com/itm/334035748519

v8 ones look like these https://www.ebay.com/itm/203186381684

if you need a riser like bondo outlines you need longer elbows made for riser set ups which are pricey or to ‘stretch’ the elbow with some exhaust hose vs the standard rubber coupler below it
 
Last edited:
Dieter said:
i think the 4.3 s use a different down elbow after the exhaust eblow on top of manifold or riser block, the v6 down elbows drop the exhaust farther forward than a v8 down elbow . I had to get different ones when swaping a 4.3 to a 5.0 maybe you have ones for a V8 ?

the v6 ones look like these https://www.ebay.com/itm/334035748519

v8 ones look like these https://www.ebay.com/itm/203186381684

if you need a riser like bondo outlines you need longer elbows made for riser set ups which are pricey or to ‘stretch’ the elbow with some exhaust hose vs the standard rubber coupler below it
Click to expand...



I believe he is referring to the "Risers" which we often refer to as "ELBOWS" that mounts to the exhaust manifold not the intermediate hard tube you are linking to.

See link
https://www.ebay.com/itm/3039473214...brand=MerCruiser&_trksid=p2047675.c101224.m-1
 
Mikey N.C. said:
Customer's regal boat, he bought knowing motor was bad. Original 4.3 vortec
with batwing exhaust manifold's. Customer bought used pre vortec ( 12 bolt intake) motor in VA. . used motor has manifolds , with risers and no spacers.
I've already dropped in motor. And have 3 set's of the elbows that are angled back toward transom. Do I need riser spacers and 90 degree elbows?
Thanks
Click to expand...

What did the original engine have? did it have a spacer between manifold and "riser" If so then you will need the same on the replacement engine.............
 
Mikey N.C. said:
How do you know static water line?
Click to expand...
Look at the dirt line on the outside of the hull, as that's the actual depth the hull sits in the water. Don't go off the stripes or anything painted on as that's not always accurate.
If there's no tell tale line of dirt or discoloration then the only real way is to put the boat in the water with full tanks and get a measurement.
 
i have done a few of these this year, you need the ones look like these https://www.ebay.com/itm/334035748519 and a set of 4" tubes. re use the tubes that came off the old manifolds for the lower section and the 4" tubes for the upper where the elbow goes into the riser.

if the original power plant used bat wing manifolds, you do not need spacers since there was no way to have spacers on a 1 piece manifold.

here is what the set up will oook like when installed

sierra-181952k7-2-01.jpg
 
Thanks guys, the original 6" on y pipes are to long , that's when I noticed, when setting in New used motor, that square boss on 90 degree elbows, was trying to go down into the 6" hose.. So I've got the straight 4"hoses and a set of the off set 4" hoses. So when I get back to that boat. I'll let you know which 1's work.
 
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