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Low idle and stalling on a Crusader 1987 350 5.7 Liter

J

junior4597

Contributing Member
I just purchased an older model Tiara with twin 350 IB's recently. Compression tests all went fine with the pre-purchase evaluation/survey and both engines had been tuned up, oil changed, plugs, wires, cap etc. I ran her about 5 times so far until yesterday when the port engine at idle started to knock a little and started to stall. I powered up a bit and she was fine but at about 2500 rpm she started to bog down and I could smell a strong odor of fuel. At about 1000-1500 rpm she stalled a few times and I had to crank her over again. She kept stalling at any rpm so realizing something was up I turned her off. I'm at a loss but here are some things I have done and am looking for possible suggestions on next steps.

  • She was sitting for 3 years prior to my purchase but the old fuel was removed (supposidly) and fresh gas put in.
  • No fuel leaks in the bilge
  • New commision tune-up a month ago
  • checked the fuel lines for brittle or cracked hoses - none
  • looked at the fuel filter, seemed clean, no residue or water on the bottom of the can
  • no blockage in any of the lines
  • fuel pump is fine as the carb gets fuel - but maybe too much??
  • used gum-out to clean the carb chambers
  • removed 2 plugs to see if there was excess fuel on the ends, all looked good
  • the carb seems to be making a louder sucking noise than the sb engine which seemed like it was fighting abnormally for more air??
  • flame arrestor was clean
  • choke and mechanics of the carb seemed to be in prefect mechanical order


I was thinking that it might be time for a carb rebuild but I'm not sure. I'd hate to have it removed and sent out if that's not it. Is there anything else I should check and or thoughts from the forum on next steps? Hard to evaluate from reading this but any bit helps!

Thanks!
 
Thanks for the reply Jeff. So I tried to be as descriptive as possible with the "symptoms" (not being a mechanic) but in your opinion these issues point back to being a carb problem? I have read other strings up here from the past with stalling issues that sounded similar and the resolutions ranged from a carb rebuild (that some times didnt work) to a coil wire replacement for a supposid fuel issue to a anti-siphon valve. Wondering if any of those should be looked at before I find a qualified mechanic and dissasemble the carb. Also, would it be a good idea considering the fuel situation with ethanol to remove the old fuel filter "cans" - I call them cans because they are just aluminum cans with the filter popped isnide - to a racor filter with water separator? Just curious moving forward. But ultimately you (and others) think this is really a carb rebuild issue?

Greatly appreciated and I will post once a resolution is presented so it can be of value to others in the future with a similar problem.

Kirk
 
Before jumping to any conclusions, make sure that the distributor housing was locked down after the tune-up.
If the housing is free to rotate, it will rotate CW in a direction that will retard timing.
Retarded ignition may cause one to appear to run rich.
Throw your light on it, and see where the advance is.

FYI: always check the progressive advance after BASE is set.
 
I will check the distributor cap but I'm pretty sure it is snug but you never know. Unfortunately I dont have the personal knowledge to test with a light, don't even have one - I'd have to get a mechanic to do that and at that rate I might as well have them continue to troublshoot it. I was thinking of actually swapping the carbs later today since I have 2 inboards. I can certainly do this on my own. In doing so I can see if the problem resolves itself with the good carb. Since it's easy to remove and install the carb I though this would be a good troubleshooting step. Anyone have serious objections to doing this?

Thanks!
 
make sure the pump pump diaphragm isn't ruptured before you pull the carb. pull the flame arrester and look into the primary bore on the starboard side. if there is liquied fuel entering that barrel (from the front of the carb), its the fuel pump, not the carb.

If you opt to swap the carb, use a 1" wrench on the filter housing and a 5/8" flare nut wrench on the nut - and use a good flare nut wrench if available!
 
So, the latest. I swapped the carbs and unfortunately the stalling/bogging and low idle issue stayed with the port engine. I even started the stb engine with the port carb and it ran just fine. So I guess by deduction I have confirmed that it is not a fuel delivery issue and not a carb issue. I guess I'm looking for some suggestions on next steps? I'm not sure if I'm thankful that it isn't a carb issue but now I'm concerned as what it could be. Valve issue? It still seems to be loud and sucking for air, louder than the draw on the other engine. Electrical? Someone mentioned coil?? I guess any thoughts would be very helpful.

Thanks
 
you only eliminated the carb, not the fuel delivery system.

If the carb isn't flooding and the pump is ok, sounds like electrical or mechanical is all that is left. maybe the tuneup wasn't "completed" or some cheap (inferior quality) parts were used. I'd rule out the fuel delivery and then go to ignition, starting with the timing curve check. could be as simple as the timing advance mechanism is stuck or the springs have rusted thru
 
Yeah; time to look at the spark advance with a light. The advance on one of my (Mopar 360) distributors used to hang up, then drop back when it felt like (the SOB!) I had timed it when it was stuck advanced so it was major retarded when it went back all the way.

This is the nature of troubleshooting: You check the most logical cause first, then trickle on down to what's really wrong.

Jeff
 
Issue resolved! I'd like to thank the folks up here for thier input - it was greatly appreciated and find this site very useful and will try to return the favor with my knowledge. End result on my situation - and it goes to show you - start small! The set screw for the breaker points wasnt "set" enough and the points weren't opening up on rotation. Took about a minute and 30 seconds to adjust the gap and reset the screw! Never mind the time I put into swapping the carbs and checking the fuel lines but what the heck - lesson learned! Kind of makes sense now - so for those out there my advice is to start small and easiest first!

Back to boating now!
Kirk
 
Another of life's litle lessons learned (the HARD way). I'll bet you'll never, ever make that mistake again!

Good man.

Jeff

NOTE: Be sure to retime that motor for it will be off a bit.
 
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