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  1. #1
    mysavannah Guest

    my starboard 454cu in 350hp crusader engine

    I've followed all of your discussions in the past year and learned a lot. Now I need some help. I have a 1986 32' Hatteras flybridge sport fish with a confounding gas engine problem. At cruise and trying to get on plane the rpms drop from 3200 rpms to less than 2500. After running a while I can't get it past 1800rpms upon attempting to plane. Tried the following: Switched carbs, replaced all fuel lines, emptied gas tank replaced with new fuel, new fuel pump, all new fuel filters, wrapped fuel line to insulate from heat. Nothing worked. Its definitely a fuel problem because it runs fine in neutral up to high rpms. and problem only occurs under load.I think it may be a vapor lock, but thought that
    insulating the fuel line would diagnose the problem. Any help out there? thanks for everything.

  2. #2
    67hat34c Guest

    crusader 454

    there are several things to check first.

    1--follow fuel line from the tank to the engine. look for a small can that looks like a check valve. it is actualy a fuel / water strainer. if it is there, open it up and take out the screen. these things were installed on some gas boats and they are nothing but trouble. they get a few drops of water in them and they restrict fuel flow. on our last boat we did the same thing you did. replaced carbs, fuel pumps etc. and problem persisted until one day my day opened up deck and sat between fuel tanks and tapped the silver can in the fuel line and the boat took off. thought it was a check valve but it turned out to be a strainer.

    2 check volts to the coil at idle and running speed. if you are getting less than 6volts then there is problem. check volts on high side of ballast resistor to rule out problem with wires, should be full 12v on high side. i would recommend you change to electronic ignition if you have not already done so. the Pertronix Ignitor and coil will help alot. You can bypass the balast resistor and get full 12v to the coil ( will need pertronix coil or MSJ coil.

    3- if you have the old mallory distributors then you may want to either replace them or rebuild them. the mechanical advance is most likely worn out. we pulled ours out and shipped them back to mallory and they rebuilt them for about 70.00 each. Kind of wish we would have upgraded to Prestolite. However the rebuild did the job along with the Pertronix Ignitors.

    4 check engine compression.

    5 check for vacuum leaks, intake and carb adaptor.

    6 are all plugs firing, check color of all plugs.

    if you want more info on the Pertronix Ignitors, i found a web site to purchase these products. very cheep, or any other items please feel free to contact me.

    Steve Hierholzer
    407 919 3198 office
    407 363 4696 home
    shierh@aol.com home e mail.

  3. #3
    Bob Bradley Guest

    Fuel starvation

    Have you checked the fuel tank vent line for obstructions, like a spider nest? Try running briefly with the fuel fill caps off to see if it is a starvation problem caused by insufficient venting.

    Are you dropping cylinders, or just experiencing an overall degradation in performance? How old are your risers? If you are dropping cylinders, could you be getting water into #7 and/or #8 due to failed risers?

    How old are the wires? Too much resistance as they heat up?

    BTW, I put the Pertronix kits on my '65 Chris Craft 327's, with outstanding results. RPMs up, fuel consumption down. Very dependable, but keep a spare on board. If one does fail, there's no fixing it. They aren't expensive - about $75 - $80 each.

  4. #4
    Scott Mather Guest

    fuel on 32

    It sounds like you checked it all but you might want to check here:

    In the fuel line on the 32' right on top of the fuel tank is a check valve, it does not look like a valve, looks just like a regular fuel fitting, it is very narrow. We had the same thing happen on our 32 Hat, I replaced everything
    and could not get it to run right. One day started to disassemble fuel line going into tank to look for an abstruction in the tank. As I was taking apart fuel line out popped a small spring and valve from the fitting that was all gumed up. Cleaned it up and ran like new.

  5. #5
    wshelton Guest

    Loss of RPM

    I had 454 Crusaders at one time although 1994 vintage which had a very puzzeling problem similar to yours. I took about the same measures you have and finally solved the problem with a $65.00 part which was the oil pressure sender switch. ( not the alarm sending unit). This part screwed into the block, under the alternator which was on the starboard side of both engines. They will go bad. I would have good RPM at start up, and run ok at low RPM. However, if you turned the engine up soon after start up the RPM would drop off, which one would think a fuel problem. This switch, if bad will think there is a loss of oil pressure and want to limit your RPM. Switch out the part from the good side for quick check, but be carefull when you unscrew it you do not break it.l

  6. #6
    mysavannah Guest

    my 35hp crusader

    Thanks Steve, Bob, Scott, and wshelton. Steve I sent you an email. How could I fail to tell you that I replaced the risers too? We checked that can, Steve, but it probably needs another look. Haven't checked the fuel tank vent line Bob but new risers are done. I'll check the wires. Found that spring and screen too, Scott, all was clean although there was a free floating cork gasket. Fixed that, still have the problem. Didn't check that pressure sending switch, thanks. I'll look into that. The problem starts usually after its run for a hour or so. I can avoid the problem, at least for a little while, by very slowly giving it gas to plane. Any attempt to normally throttle up to plane with more fuel leads to drop off of rpms.Thanks for all the pointers. I'll let you know how it goes, Fred

  7. #7
    67hat34c Guest

    crusader 454

    there still may be a second can in the line that is a water strainer. some older boats had these. problem with these as they are way too small, a little water cloggs them up and wont allow enough fuel to flow.

  8. #8
    garyd Guest

    fuel problems

    I have gone through all kinds of fuel problems. In fact at the marina I worked at we delivered over 100 new boats a month for months on end. Just about every make and model. This did not include used boats.

    The fastest easiest way to determine the problem is this.
    Get a 5 gallon, I prefer plastic, fuel can hook it up so it gravity feeds into the carbs. normal pick up.

    Start and run the engine as normal. This bypasses many items. You can then find out if the engine runs normal. If it does you know for sure the problem is up stream from that point.

    We could get a new boat off the trailer preped and checked out in less than an hour using this little trick. Then we would add fuel to main tank and take the boat for a ride. Many times we came back using our rigged can.

    We then set out to find the problem. Mud dappers nests,
    fiberglass in the tank, kinked hoses, check valves installed backwards, two 0 rings on fuel water seperator lets air in doesn't leak fuel, plugged pick ups, plugged vents, and on and on and on.

    If it runs great with the gravity fuel but not hooked up to the ships fuel line,then back track. Hook up the can to the fuel pump inlet. If again it runs normal then you can bet it is in the tank or vent. Take the hose off the tank try again. By now your getting the picture.

    good hunting


    p.s. On one of my very own boats it was a hunk of mud in a ninety degree fitting. Very difficult to see, once I isolated the problem and looked very close with a fashlight I saw it, but not before even though I looked it over a couple times.

  9. #9
    Jackman Guest

    my guess

    If you still have the original engines for your boat....Did you check the distributor for corrosion? If the springs and all the internal parts have corrosion this will keep you from getting the proper amount of advance/spark while under load. I had the exact same problem in my 1985 32' FB and it turned out to be a bunch of rust on the distributor parts. Take the cap, rotor and coil out of the distributor and look for any sign of rust...clean out and spray with WD40 or replace the parts (I think some of them are hard to get, which is why I just cleaned them up) The only reason I say this might be the issue is because it happened at the exact same RPMs that your experiencing your problems. I think that the distributor has enough output without the advance mechanism working to get you to 3000rpms, but will then drop while underload because it needs to "open up" by centripital force....creates a lean condition which will lead to burnt/blown pistons if you run with the issue too long.

  10. #10
    jrsulo Guest

    Re: my guess

    Have you looked at the pick-up tubes on the fuel tank ?? I had a problem many years back,seems the weld on the pick-up tube was cracked . was not real bad when the tanks were full,but real bad when less than half full.do you have a fuel tank for each engine??......just thought this might help.

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