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454XL difficult to start....hmmmm

Ply

Ply

Contributing Member
This has to be the most common annoying question asked but it's my turn...

I have a 94 454XL carburated engine that is very difficult to start but once running and warm it runs great and then will starts back up NO problem what so ever after she is warmed up.

Typically I go around 7 days in between attempts in starting the motors.

I am cautious not to flood engines so I typically pump the throttle handle 3-4 times max but seems like I end up needing to pump it a few more to get it running.

The motor just seems to crank and crank and will finally start after maybe 4-5 long cranking sessions.

Should I pump her more in the beginning? Less does not work as I tried that this weekend...

Any suggestions where I should start to solve this???

Thanks all....

PLY
 
If carbedengines have not been started for a few days, the carbs must be “topped off” bythe fuel pump to make up for gas that has evaporated or back flowed from thefuel line. Your 454XL fuel pumpsinitially run while the starter is engaged. To top off your carbs without cranking the engine, put the transmissionin gear and turn the ignition key to start. Do this carefully at first to ensure your neutral safe switch on thetrans prevents the starter from engaging. After a few seconds the fuel pump should have recharged the carb. Return the trans to neutral and try andstart. The only other possibility wouldbe a choke problem but engines usually start pretty easily in warm weather whenthe choke is stuck open. None of this would apply in a FI engine. If your pumps do not run following the aboveprocedure the problem may be your oil pressure switch located behind thealternator. That switch turns offstarter circuit power to the fuel pump and switches to 12 VDC system power whenthe oil pressure comes up. If yourstarter-to-pump circuit is not working, your pump may not kick on until oilpressure comes up during cranking. Please advise how your caper ends. Good Luck.

FL Panhandle
 
Mulletwagon said:
If carbedengines have not been started for a few days, the carbs must be “topped off” bythe fuel pump to make up for gas that has evaporated or back flowed from thefuel line. Your 454XL fuel pumpsinitially run while the starter is engaged. To top off your carbs without cranking the engine, put the transmissionin gear and turn the ignition key to start. Do this carefully at first to ensure your neutral safe switch on thetrans prevents the starter from engaging. After a few seconds the fuel pump should have recharged the carb. Return the trans to neutral and try andstart. The only other possibility wouldbe a choke problem but engines usually start pretty easily in warm weather whenthe choke is stuck open. None of this would apply in a FI engine. If your pumps do not run following the aboveprocedure the problem may be your oil pressure switch located behind thealternator. That switch turns offstarter circuit power to the fuel pump and switches to 12 VDC system power whenthe oil pressure comes up. If yourstarter-to-pump circuit is not working, your pump may not kick on until oilpressure comes up during cranking. Please advise how your caper ends. Good Luck.

FL Panhandle
Click to expand...

Mulletwagon,

Thank you for your very thorough reply.

Bare with me, long time outboard guy that's re-learning my Crusaders (And loving them I might add!!!)

Couple questions, Mullet.

1) So I'm assuming in a 94XL 454 the fuel pump is electronic, would that mean when I physically "pump" the throttle levers on the helm I am NOT pumping fuel into the carbs?? (Eliminating concerns about flooding when my 3 year old is playing with them...lol)

2) If the caper is oil pressure switch related, what would make it so the motor eventually cranks over? Will oil pressure build while only turning the motor over such it would disengage that circuit?

Thanks again for all your help.
 
Yes, your pumps should be electric and are located on theforward right side of the block. If the carb fuel level is up, repeatedlyadvancing the throttles will flood the engines. When you are cranking the engine a helper should hear (or feel with ahand on it) the pump working. The olderoil pressure switches are problematic and often result in the presentation youdescribe. Sufficient oil pressure will eventually build during cranking toclose the switch and energize the pump - which may be what is happening in yourcase. I had the exact same situation a year ago and the fix was a new (big $$)pressure switch. Recommend checking all the switch circuitry before getting anew switch. Should be fairly easy to trouble shoot. Hang in there !
This might be helpful:
http://www.marinepartssource.com/crusaderpb/454xl.asp

 
Thanks, Mullet... I'm letting the boat sit for a few more days until I try the "priming" technique you spoke of but I'll surely post it to the board.

Do you recall the cost of that oil pressure switch??
 
Ply,

Is this happening to both engines? Do they have Rochester Quadrajets?

To see if the fuel is leaking or evaporating out of the carb, as suggested above, try this. Before trying to start it next time after it has been sitting for several days, remove the spark arrestor from the carb, manually block the choke open so you can see down inside the carb, and then watch for a spray of fuel into each barrel when the accelerator is pumped. You can easily disconnect the cable from the helm to the carb so you can manually operate the linkage at the carb. There is an accelerator pump lever at the top of the carb that gets pushed down to force fuel into the carb venturi IF there is fuel in the bowl. If no fuel seen, just turn the ignition key on for a couple seconds, then off, then on and off again a few more times. Then try the test described above again at the carb to see if fuel is now getting pumped into the throat of the carb. If you now see fuel, this is when pumping the throttle once or twice and then leaving it about halfway open will help to start the engine. Don't forget to unblock the choke and reconnect the linkage if disconnected.
 
erich said:
Ply,

Is this happening to both engines? Do they have Rochester Quadrajets?

To see if the fuel is leaking or evaporating out of the carb, as suggested above, try this. Before trying to start it next time after it has been sitting for several days, remove the spark arrestor from the carb, manually block the choke open so you can see down inside the carb, and then watch for a spray of fuel into each barrel when the accelerator is pumped. You can easily disconnect the cable from the helm to the carb so you can manually operate the linkage at the carb. There is an accelerator pump lever at the top of the carb that gets pushed down to force fuel into the carb venturi IF there is fuel in the bowl. If no fuel seen, just turn the ignition key on for a couple seconds, then off, then on and off again a few more times. Then try the test described above again at the carb to see if fuel is now getting pumped into the throat of the carb. If you now see fuel, this is when pumping the throttle once or twice and then leaving it about halfway open will help to start the engine. Don't forget to unblock the choke and reconnect the linkage if disconnected.
Click to expand...

I feel like such a rookie as I don't even know what carb is on her. She is new to me this season as I'm coming from outboards :-( Will a photo of the carb help ID the brand?

Erich this is NOT happening to both engines. Starboard fires right up. I'm currently letting her sit another day to simulate my last experience but will be heading down in next day or two.

SOOO I first want to see if pumping the throttle lever sprays fuel into the barrel, correct... If it is not that would mean I have no fuel in the bowl??

I will then engage the tranny and turn the key (Carefully in case it really turns over) and I should expect the electronic fuel pump to fill the bowl? Will I be able to hear this? After this giving the throttle a pump or two should now actually introduce fuel. Have I got this right? (also a bit confused as to whether I have to actually turn the key like to start it or just to the first click)

Last question. Accelerator pump? Is that what bring fuel from the bowl to the barrel ONLY?? Electronic fuel pump actually fills the bowl?? Just trying to learn the dam pathway!!

This forum has never been anything but great help. Thanks again to all!
 
Also guys can ya'll suggest a manual that I can buy that I can refer to so as to learn these motors better??

I have the original operation and maint. manuals but I want something a bit more in depth???

Price is NOT a concern.
 
Ply said:
I feel like such a rookie as I don't even know what carb is on her. She is new to me this season as I'm coming from outboards :-( Will a photo of the carb help ID the brand?

Erich this is NOT happening to both engines. Starboard fires right up. I'm currently letting her sit another day to simulate my last experience but will be heading down in next day or two.

SOOO I first want to see if pumping the throttle lever sprays fuel into the barrel, correct... If it is not that would mean I have no fuel in the bowl?? Correct

I will then engage the tranny and turn the key (Carefully in case it really turns over) and I should expect the electronic fuel pump to fill the bowl? Leave the shift lever in neutral and only turn the key to the ON position but not to the second START position. Will I be able to hear this? I don't know. After this giving the throttle a pump or two should now actually introduce fuel. If fuel has now filled the carb you should see it spraying into the throat of the carb. Have I got this right? (also a bit confused as to whether I have to actually turn the key like to start it or just to the first click) Just to the first click (ON position) to momentarily operate the fuel pump

Last question. Accelerator pump? The accelerator pump is basically just a plunger in a section of the carb that forces some fuel that is in the fuel bowl (bottom section of carb) into the carb throat and down into the intake manifold which then sucks it into the cylinders when you turn the key to the start position. Is that what bring fuel from the bowl to the barrel ONLY?? Electronic fuel pump actually fills the bowl?? Yes the electric (not electronic) fuel pump would normally fill the fuel bowl. There is a small needle valve in the carb bowl that will shut off the inlet when it is full Just trying to learn the dam pathway!!

This forum has never been anything but great help. Thanks again to all!
Click to expand...

See my bolded inserts above.
 
Turning the key just to "on" will only activate the fuel pump (momentarily) on FI engines (unless the pump has been hot wired to the ignition switch which is sometimes done to avoid buying a new oil pressure switch). This is a safety thing which prevents the fuel pump from running if the engine is not running. On carbed engines electric pump power only comes from the oil pressure switch.
 
Mulletwagon said:
Turning the key just to "on" will only activate the fuel pump (momentarily) on FI engines (unless the pump has been hot wired to the ignition switch which is sometimes done to avoid buying a new oil pressure switch). This is a safety thing which prevents the fuel pump from running if the engine is not running. On carbed engines electric pump power only comes from the oil pressure switch.
Click to expand...

Mullet,

My engines are FI and is the behavior I was thinking of regarding the fuel pump. Ignition switch on for a few seconds and then off a couple of times to prime the system. If oil pressure is needed to even temporarily operate the fuel pump on a carb'd engine, how can he fill the carb fuel bowl if it is in fact empty? Will he actually have to crank the engine to build up oil pressure so that the fuel pump operates?

Ply,

Sorry if I gave you some incorrect info. :(

Erich
 
Hi Erich,
Yeah, the carbed Crusaders are old school. When starting,the fuel pump runs while the engine is cranking (operating initially off of thestarter-to-slave solenoid circuit). Oncethe oil pressure comes up (usually when the engine starts) the pressure switch disconnectsstarter power to the pump and switches to system power. Usually this system results in a fairly quickstart. If the carb is dry (or new waterseps have been installed) it takes time for the pump to charge the system withfuel. Continued cranking will workbecause the pump is working as long as the starter is engaged. Continued cranking will also eventually bringup the oil pressure to the point the pressure switch will divert battery powerto the pump. A better technique to topoff a dry carb is to put the trans in gear and turn the key to “start”. If the trans neutral safe switch is working,ignition switch power will not go past the slave solenoid, the starter will notengage, however, the fuel pump will still run. FI engines are of course a lot smarter. The computer knows when to turn the pump on oroff (brief on to prime, permanent on with rpm, and shut down with no rpm) andis usually pretty reliable. The FI 454salso deleted that #@*! expensive and troublesome oil pressure switch. HTH
Ed


 
Not exactly for the carb'ed engines...and it varies with the vintage....there have been a couple modifications over the years. the more recent editions power the fuel pump, during cranking, off the ignition terminal of the starter solenoid and use a normally open switch (controlled via the oil pressure) single pole switch to drive the pump off the ignition feed. the earlier variations used the SPDT switch (again, oil pressure controlled) to satisfy the safety requirement. I'm sure there are others but the scheme is a modification of the above....Now, adding an ECU introduces a lot more options and the MEFI-5's can even monitor the fuel pressure in the rail...bottom line is I wouldn't expect the fuel pump to run with the key in cranking and the gear engaged...its easier to add a momentary 'primer button' that to rework the wiring.
 
Concur on use of "I" terminal on slave or primary solenoid for power to the fuel pump during cranking. That terminal used to be used for higher voltage to the coil during starting before HEI. Some caution on rigging a priming circuit is warranted. Sending 12VDC directly to the pump will actually engage the starter on the older XLs on an otherwise unmodified system (unless the trans is in gear). Interesting thread !!
 
The only I (or R) terminal is only on the main starter solenoid, not the slave.

And 2x on the caution is warranted doing priming circuits mods....
 
Keep this dialogue going guys because I'm learning from every comment. Right, wrong or indifferent it's all appreciated.
 
makomark said:
The only I (or R) terminal is only on the main starter solenoid, not the slave.

And 2x on the caution is warranted doing priming circuits mods....
Click to expand...

Mullet went down tonight. No luck with attempting to prime her your way (Which is EXACTLY how the operation/maint manual instructs me to do)....

I got desperate and gave her a squirt of starter fluid and SHAZAAAAM she fired immediately up of course. She also would re-start easy peasyyy which is the norm... I mean she re starts NO problem.

What say you??
 
Hey Ply,
Sounds likeclassic pressure switch failure – but more testing is recommended. Might trythe in-gear, turn key to start on your good engine and confirm the pump runseven though the engine is not cranking. Assuming the pump runs (and it should),try the same procedure on the problem engine. If the pump is not running it means one of two possibilities. Either thepressure switch is bad or the starter wiring to the pressure switch is anissue. My guess would be that thestarter wire going to the pressure switch is not making internal contact (badswitch) with the pump wire (has purple on it) , however, the mechanism thatconnects system voltage to the pump wire when pressure is sensed isworking. This would explain why amanual prime lights off the engine and it keeps running (after not beingstarted for a few days). Once theengine starts the carb level is up and restarts are not a problem. A finalcheck would be to disconnect the three-wire connector at the pressure switchand confirm the starter circuit wire (usually has yellow on it) is putting out12 volts when the key is in start while the engine cranks (or the trans is ingear). If voltage is at the starterwire at the pressure switch connector, the pressure switch is the culprit. Something else you can try (after the enginehas not been run for a few days) is to run the pump momentarily by putting batteryvoltage to the pump circuit breaker located in the electronics box on the rightexhaust elbow. This will top off the carb and will probably result in theengine starting. Be sure to have thetrans in gear or the starter will engage when voltage is put to the pump. Afinal check on the pressure switch would be (connector disconnected) to checkcontinuity between the purple wire and yellow wire to confirm voltage wouldflow into the switch from the starter circuit and out the purple wire to thepump. Hope you can get to your pressureswitch without too much pain. Access tothe switch on my port engine is a bear. Think you are getting close to breaking the code. Looking forward to the details of yoursuccess story !

Ed

 
Mulletwagon said:
Hey Ply,
Sounds likeclassic pressure switch failure – but more testing is recommended. Might trythe in-gear, turn key to start on your good engine and confirm the pump runseven though the engine is not cranking. Assuming the pump runs (and it should),try the same procedure on the problem engine. If the pump is not running it means one of two possibilities. Either thepressure switch is bad or the starter wiring to the pressure switch is anissue. My guess would be that thestarter wire going to the pressure switch is not making internal contact (badswitch) with the pump wire (has purple on it) , however, the mechanism thatconnects system voltage to the pump wire when pressure is sensed isworking. This would explain why amanual prime lights off the engine and it keeps running (after not beingstarted for a few days). Once theengine starts the carb level is up and restarts are not a problem. A finalcheck would be to disconnect the three-wire connector at the pressure switchand confirm the starter circuit wire (usually has yellow on it) is putting out12 volts when the key is in start while the engine cranks (or the trans is ingear). If voltage is at the starterwire at the pressure switch connector, the pressure switch is the culprit. Something else you can try (after the enginehas not been run for a few days) is to run the pump momentarily by putting batteryvoltage to the pump circuit breaker located in the electronics box on the rightexhaust elbow. This will top off the carb and will probably result in theengine starting. Be sure to have thetrans in gear or the starter will engage when voltage is put to the pump. Afinal check on the pressure switch would be (connector disconnected) to checkcontinuity between the purple wire and yellow wire to confirm voltage wouldflow into the switch from the starter circuit and out the purple wire to thepump. Hope you can get to your pressureswitch without too much pain. Access tothe switch on my port engine is a bear. Think you are getting close to breaking the code. Looking forward to the details of yoursuccess story !

Ed
Click to expand...

Where is the pressure switch located??

I'm in a 29 Blackfin Flybridge.. You're a Blackfin guy also right??
 
Got a 29 Blackfin FB too. The switch is right behind the alternator on the block. Easier to see on your starboard engine for reference.
 
Mulletwagon said:
Got a 29 Blackfin FB too. The switch is right behind the alternator on the block. Easier to see on your starboard engine for reference.
Click to expand...
Ahhh yes of course. Couldn't think of a worse location.Alternator must need to be removed? Anything else that you recall?I'll do the troubleshooting you mentioned this weekend first.
 
There are three wires on the pressure switch. One goes to a 12 VDC source, one splices into the starter wire that goes from the ignition switch to the slave solenoid, and one goes to the fuel pump through the circuit breaker. Looked at my pressure switch today. Once it is unplugged, should not be too difficult to unscrew out.
 
hi, mine seem to do the same thing. '94 454 xl's. I try different combos, its frustrating to see a buddys boat start right up. the key to mine seems to be letting them not sit for a week, as mentioned. once theyve been running, they do start right back up. i did find the stbd motor had the oil switch connected loosley (secured by electrical tape from previous owner) and that helped. and i think the same motor, i replaced the fuel pump too. i dont like to pump and pump the throttles, but that seems to be what makes them happy.
 
Saltshaker said:
hi, mine seem to do the same thing. '94 454 xl's. I try different combos, its frustrating to see a buddys boat start right up. the key to mine seems to be letting them not sit for a week, as mentioned. once theyve been running, they do start right back up. i did find the stbd motor had the oil switch connected loosley (secured by electrical tape from previous owner) and that helped. and i think the same motor, i replaced the fuel pump too. i dont like to pump and pump the throttles, but that seems to be what makes them happy.
Click to expand...

I've actually taken the same approach not letting the boat sit!!! Especially with gas prices under $3 at the Marina.... Loving it.

If by chance she acts up I am guilty of hitting her with a squirt of starting fluid. I do NOT want to continue this but I also don't have time to fix her right now as it's mid-tuna mania here...

I plan to swap out the oil pressure switch when things quiet down and go from there.
 
For those with the SPDT pressure switch (controlling the electric fuel pump), you can easily add a momentary "primer button" switch (SPST-NO type) to eliminate the hard to start syndrome (when caused by fuel evaporation/drain back).
 
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