Logo
FULL SITE MENU

1987 Crusader 454 bogs down at 2800 rpms

L

lazydaze

New member
I have dual 1987 Crusader 350hp 454 engines with Rochester carburetors. The port engine starts and runs great until I get up to around 2800 rpms I believe when the secondaries are kicking in. At that point it falls over and bogs down to around 2200 rpms. It then catches again going back to 2800 and starts the cycle again. I get a lot of white smoke and the smell of fuel when it happens. The engine doesn't overheat and I'm not losing a bunch of coolant. I don't see any evidence of water in the oil. I have rebuilt the carburetor and replaced float. I replaced the coil, wires, spark plugs, rotor and distributor cap but no luck. The fuel filter looks brand new. There doesn't seem to be a whole lot left. I'm at a loss...any help would be greatly appreciated.
 
I"d swap carbs port to stb. See if the issue follows the carb. Sounds like carb issue. But, have you done a timing check?
 
+1, went through the same thing last year. I carry and extra anti-siphon valve with me but you can clean them out, it's just a ball bearing and spring inside. On my boat the valve doesn't jump out at you, it's simply the part that the fuel line connects to but just looks like a fitting installed.
 
''the fuel filter looks brand new''......this can be misleading.....run your finger on the inside of it if its a cylinder filter and look closely for a kinda residue...if its bad enough it can be sticky....you can blow thru a bad filter and it will seem ok by the way...
 
If you have a buddy, it's easy to see if the bog is fuel supply related: Practice slipping the choke on via the linkage, then take her for a spin. When the bog occurs, add some choke and see if it goes away.

If it does--then gets far worse--your not getting gas to the carb (which is okay--one down).

If it picks up and continues making power
 
bobct said:
you can also remove the gas cap if u want to test anti-siphon issue.
Click to expand...

bobct,

I don't understand what you mean. If you think you may have a clogged tank vent line, then, yes, removing the filler cap will help prove it, but how is that a test for the anti-siphon valve???

Erich
 
Loosening the fuel cap on the tank fill port usually is used to test for a restricted vent line.

When the carb was rebuilt, did the air valve spring get checked and adjusted? is the dashpot functioning? Sounds as though the air valves are not responding correctly and you are experiencing a lean condition...black smoke would indicate a rich condition.
 
Back
Top