“Oh right, because you walked into strippers discount warehouse and said ‘Help me showcase my intellect.’” - Archer
Bill
Grand Rapids, Michigan
1985 Donzi Criterion SS
1967 Donzi 16 Ski Sporter, C16-409, Has a new home!
38' Carver Aft Cabin
1968 Sea Ray SRV 180 w/1975 70 hp Evinrude
10" RIB w/15 hp 1984 Evinrude
photo 2.JPGphoto 4.JPGphoto 8.JPGphoto 9.JPGphoto 10.JPGphoto 6.JPGphoto 5.JPG
Plug on left is #6 and right is #4 4th pic shows number of 8050B
Since this is an automotive carb, would I be better to purchase a marine carb probably a 0-80551 Holley or Mallory Any other suggestions ? Thanks to all who have taken the time to answer.
Trevor
Canada
here's my take on the pic's >
get rid of that spacer
by looking at the plug strap color the timing is pretty close, might stand to be advanced another 2*...
good upper ceramic color ring on the lower plug, lean on the upper plug, gaps look different, I can't see the lower internal ceramic color, but what I do see is very typical of a badly jetted dual plane intake, with maybe partially plugged main housing air bleeds
the 80457-5 isn't on my chart... but I would throw in a pair of 69 front jets and a new 6.5 PV in the front side, kill the spacer, and get a 1/4" bakelite spacer instead, advance the timing 2*, no more than 32* total and see what happens for giggles
if the timing is already there, then you have crappy slow burn fuel because I see some residue on the strap that shouldn't be there
Thank you Jim for looking at the pictures. My concern now is that this is an Automotive carb. There is no place to connect the overflow tube from the fuel pump. I believe this is a fire hazard. Would a Holley 0-80551 (4160 or Mallory equivalent work.
Thanks
Trevor
Trevor
Well the carb is a vacuum secondary carb not mechanical. You can see the vacuum actuator in the picture of the carb from the opposite side of the throttle linkage (picture #6). The secondaries will never open when you open the throttle all the way without the engine running, it only opens with vacuum.
There is a small vacuum port coming out of the metering block (picture #6 also) that is open, that needs to be plugged or connected to the distributor, but being this is a boat engine and there is usually no vacuum advance in the distributor, you should plug it.
On the secondary actuator it says Performance Carb. these carbs are usually jetted richer then standard automotive 4150/4160 carbs.
One more point, make sure the choke plate is under spring tension to stay open all the time if you are not using it, by rotating the black choke housing.
Just adding to what has already been stated.
Good luck
Steve
ps Presently also in Canada (Montreal area working)
Info on id'ing the type of carb
http://www.cpperformance.com/t-carbu....aspx?skinid=5
Member - WAFNC
1997 22 Classic (sold)
1997 Formula 271 Fastech
502 Mag MPI
machinist ,bore it deeper,ream it bigger, and lap it to a fine finish
https://www.facebook.com/photo.php?v...=2&theater
I tried my 400, with and with out a thermal spacer. I used a single plane 1" spacer .I lost 250RPM right off the top by taking it off. It did have slightly better throttle response at lower RPM with out it. But 250 RPM loss is huge. I think your onto something with the power valve. A vacuum gauge is always handy when setting up a Holley
machinist ,bore it deeper,ream it bigger, and lap it to a fine finish
https://www.facebook.com/photo.php?v...=2&theater
problem is, he has a dual plane intake... and a thermal spacer doesn't have the ribbed internals, and isn't metal either... a spacer is used to tune runner length characteristics and can be VERY beneficial up top, mid range not so much.. as was pointed out before, that open vacuum nipple and too small jets could be the only issue.. good catch on the open vacuum nipple, as that is a ported nipple and really only see's a vacuum reference once the throttle is opened..
Since he has an automotive carb his best move would be to find a marine 650, 750 on a 350 is a bit much. I run a 750 on my 383, I think it would run nicer with a 650. A 650 may take a tiny bit off my top end but who cares!!!!
No matter what your beliefs are "GOD BLESS AMERICA"
Fully retired marine tech near 60 years in the biz.
Thank you, Patrick
1994 18' Classic 350Mag Alpha
Previously owned Donzis -
1996 22' Classic, 502Mag Bravo
1987 20' Minx, 350Mag Alpha
1975 18' Classic, 350Chevy Volvo 280
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