Johnson V4 Inner Inner exhaust (baffle) plate hole size difference

[spybot]

Hi All
Long story short i built a V4 140hp had a blow out from the crankcase so now a rebuild is in store.
I have tried to remove all casting flaws for a free flowing fuel flow.
Now starting the build i have 2 inner exhaust plates to chose from. Both are different parts numbers, not only that but a massive difference in outlet port size.
The one on the left as you can see is about 25% bigger but it has the rib that needs to be removed is there any other tweaks i can do to make this a smooth a path as possible ???458240458241

[Kennay]

For what it's worth, the one on the left is the same as my 95' 112.

[Dave S]

I have ...in my yard.... a 140 block.... been kickin it out of the way.....But lookin at it I would think you could do some..... grindn on the block to have better flow.....good luck from this side of the pond.....

[hsbob]

remember these are tuned exhaust 2 cyc motors. larger porting size may not help clear the cylinder of exhaust gases.

be sure the web on the block has the 1/2" x 1" cut out

[powerabout]

thats a 135 and a later version, different filler blocks as well

[racervboat]

If its a 140 block it has the cut out.Oval one is old 1973-4-5 use the other one that's the later style,take the stuffers out of the block and use them as garage wall art.But what the hell do I know.

[rjdubiel]

If its a 140 block it has the cut out.Oval one is old 1973-4-5 use the other one that's the later style,take the stuffers out of the block and use them as garage wall art.But what the hell do I know.

He doesn't know anything, just use to race against the fastest roundy-round V4's back in the day!

[ssv170]

Question for racervboat, why leave out the stuffers?

Tia

[powerabout]

Hi All
Long story short i built a V4 140hp had a blow out from the crankcase so now a rebuild is in store.
I have tried to remove all casting flaws for a free flowing fuel flow.
Now starting the build i have 2 inner exhaust plates to chose from. Both are different parts numbers, not only that but a massive difference in outlet port size.
The one on the left as you can see is about 25% bigger but it has the rib that needs to be removed is there any other tweaks i can do to make this a smooth a path as possible ???458240458241


you will need the correct stuffers to suit whatever manifold you use or make your own to match

[racervboat]

Question for racervboat, why leave out the stuffers?

Tia If you look at the stuffers in the block on all 4 ex ports the outside ports on each cyl hits a very sharp exh wall to get the exh out like all of the flow goes to the middle of the stuffer and chokes the flow so taking them out is like open flow headers on a car motor, so think of the bubble back without the stuffers as headers for the exh.Now all three ports of each cyl have an open easier flow to the bubble back/header.Remember we are talking about a consumer fishing motor so the factory did em that way so the motor don't loose bottom end planning torque.So us s&fllyers don't need that on a small light boat.Its been tried and true like the 9 page build left out page 10 haha .Ask gary here aka olboatman he has one of my mod motors on his viper with no stuffers in it im not talking chit.So now let the bashing on my ass begin.

[powerabout]

If you look at the stuffers in the block on all 4 ex ports the outside ports on each cyl hits a very sharp exh wall to get the exh out like all of the flow goes to the middle of the stuffer and chokes the flow so taking them out is like open flow headers on a car motor, so think of the bubble back without the stuffers as headers for the exh.Now all three ports of each cyl have an open easier flow to the bubble back/header.Remember we are talking about a consumer fishing motor so the factory did em that way so the motor don't loose bottom end planning torque.So us s&fllyers don't need that on a small light boat.Its been tried and true like the 9 page build left out page 10 haha .Ask gary here aka olboatman he has one of my mod motors on his viper with no stuffers in it im not talking chit.So now let the bashing on my ass begin.

Is that for the 135 style as well as the 140 style?

[racervboat]

Is that for the 135 style as well as the 140 style? Ive never ran or raced a 135hp block but would think it would be the same.Funny I took a trade-in last year1983 90hp with a bubble back on it when I tore it down it was a 90hp and someone installed stuffers and a oval bubble back from a 1974 and newer stuffers he said it ran very good till it lost a ring.I did not think or had even tried to do that but it fit and ran but not a very good match from oval to the newer style stuffers.

[olboatman]

I have one of racervboat's V4 OMCs that he built as a back up mota for his race boat back in the day. I can attest to his post about leaving out the exhaust stuffers as my mota he built will turn 7400 rpm all day long and has serious mid range pull. My Viper does over 80 with the right prop and has no problem jumping on plane. I agree that the stuffers were there for consumer boats as l had a stock 140 on a Carlson CVX and can both hear and feel the difference. If you are looking for top speed and have a moderately light performance boat leave the exhaust stuffers out!
Gary

[racervboat]

I have one of racervboat's V4 OMCs that he built as a back up mota for his race boat back in the day. I can attest to his post about leaving out the exhaust stuffers as my mota he built will turn 7400 rpm all day long and has serious mid range pull. My Viper does over 80 with the right prop and has no problem jumping on plane. I agree that the stuffers were there for consumer boats as l had a stock 140 on a Carlson CVX and can both hear and feel the difference. If you are looking for top speed and have a moderately light performance boat leave the exhaust stuffers out!
Gary Kinda sounds like this :Dhttps://youtu.be/PJldRUYzo7o

[FMP]

Never gets old

[racervboat]

Never gets old That's right frank,that video is a mod motor with stuffers in it hahaha

[FMP]

Just put goosebumps everywhere lol

[ssv170]

Prolly not a good idea on 1500 # boat.

Thanks