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454xl TBI not building power.

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ronjenkinsdc

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I have a 1998 Crusader xl TBI that has a few issues, and my local mechanics don't have time to help. So, here goes: starts fine, run smooth at idle and up to about 1300 rpm's. When trying to get on plane, I must slowly increase rpm's, with a bit more work from the starboard motor to help the problem port, building to about 2000 rpm's and she'll cruise at 20 kt's, although temping up to 225 degrees. When trying to increase throttle, the port backs off hard and abruptly, allowing me to slowly build back up again to 2000rpm's. If I try to plane out normally from 5-10kt's, it builds no power, instead, kind-of bogging down.

I've inspected the belts, and the raw water pump belt was ridiculously loose. Probably the issue with the white smoke.
I've replaced the alternator, raw water impellar, risers, manifolds, exhaust hoses, plugs.
Any help would be great. Maybe a "Troubleshooting Flow Chart' of sorts.:cool:
 
Am I correct in reading that at 2000 rpm's your boat is doing 20 knots? What are the maximum rpm's your motors will turn? I'm thinking you may be
overpropped. You are definately overheating at 225 degrees. Have you cleaned/replaced the fuel filters, my 1997 454 XLi has 3 filters per engine.
How long has the boat been performing in the described manner? Bob
 
My tach's don't work properly, so I'm guessing at 2000rpm's. Could be more. Gps reads 20 knots though. I tightened the raw water pump belt. hopefully she'll run cooler. I didn't know about three fuel filters. I had changed the filter above the fuel pump. I found another filter in front of the 'carb/TBI/spark arrestor. I will change that one and see if that does it. Where might the other filter be. I checked the manual, and it doesn't mention a third filter. Also, my manual says '454XLi' on it, and my spark arrestor covers have a decal that says '454XL' Are they basically the same? I also have a round, flat, black. pancake looking thing that the fule lines go thru. Is that a filter of sorts, or ?
 
Taking a quick shot at this simply by the similar symptoms we had experienced ourselves, this sounds a lot like the clogging of the transmission / oil U cooler on the front right hand side of the engine (engine oriented with fan belts facing forward)

It has a tendency to clog and need cleaning every two years or so, particuarly around the lower U shaped bottom area right near to the removable zinc location. Often times the coroded zinc itself will cause the overheating, then your computer kicks in and very rapidly and suddenly will cut back the engine automatically with its overheating protection program, usually cuts it back down to around the 2000 RPM. The good news, if this is your problem, is the U cooler is easy to replace or clean out in an acid bath. Sometimes just a clothes hanger wire can ream out the zinc blockage as well, and that was our easiest solution during a few different occurences over 12 years of ownership of the same engine. If I recall the cooler for a new replacement was only US$200 or so as well.

Could be alot of different things, but this comes to mind ... It was one of the easiest repairs, compared to many Try this and good luck. Allenb
 
PS ... that black hockey puck is what they called an Oblesk filter ... its a screen filter for large particulates and is your 3rd filter

XLi was the designation used by Crusader for fuel ignition instead of the earlier and plain XL model which was of carburators
 
'white smoke' usually indicates coolant on a gasoline engine; I'd check the heat exchanger and make sure it is full. May also give the exhaust hoses a good going over as they won't tolerate low water flow into the exhaust for very long.

You mentioned manifolds but not risers and elbows; when was the last time they were changed?

The 'hockey puck' is called an Oberg filter.
 
I will R/R fuel filters. I will remove 'U-tubes' and R/R them. I will remove heat exchanger and R/R it. I will check hoses. Couple of questions: The fuel system is under pressure from what I understand. Do I need to release the pressure prior to removing the filters? If so, how. Also, can the in-line filter and the 'hockey-puck' Oberg filter be simply cleaned and checked for flow, or is it necessary to replace these? When removing the U-tube, anything I should know about, or is it as simple as it looks? What about a fuel injector problem? Could this be involved? A friend suggested that might be the problem, although he is not a mechanic.
 
do one item at a time then run the boat and check for cure, therefore you will learn what the problem is or was.
The hockey puck filter comes apart in half. You will need to shut off your fuel flow to it, usually there is a valve nearby just up line towards the fuel tanks
There is a simple screen filter inside. Simple maintanence, as well as the U cooler. both are easy. we would do them first and cross them off the list.
Go from simple to complex when troubleshooting. Use good logic... ab
 
I R/R'd the heat exchanger and the U-tube. Replaced thermostat and coolant. Ran boat, never got over 190 degrees. But, I still have to power her up slowly, or the port motor backs-off abruptly. I can work throttle back and forth and build power, but something is wrong. There is a small cylindrical thing that the fuel line goes thru. Looks like a small solenoid. Could that be the fuel shut-off, or what? It is located between the tank and the fuel pump. I will check the Oberg filter and the inline filter next. But I can't find the fuel shut-off. Is it necessary to shut-off the fuel, or can I just slowly loosen the fittings?:confused:
 
You can relieve the pressure via the Schrader valve. Just be aware that there will still be liquid in the line.

The Oberg filter can have the screen cleaned or replaced.

The fuel shut-off valve should have been installed by the boat builder; gasoline engines don't need one so you shouldn't expect to find it on the engine.

190 is still warmer than it should be unless you're pumping bath water thru the seacock - can you keep your hand on the exhaust elbows with the engines running?
 
Schrader valve? What does that look like. I can keep my hand on the elbows while running, it is pretty warm, but not hot. I did put 190 degrees thermostats in. Should I have a lower type? There is a valve in the fuel line near the in line fuel filter above the intake manifold. It looks like a valve stem on a tire. Can I release the pressure there?
 
190's a bit warm for a thermostat in a boat, especially if you boat in the brine. I think 170 is the standard one from the factory (newer engines) and 160 for the mark IV blocks.

Some people refer to the Schrader valve as a tire's valve stem so glad you got it. Be careful when you relieve the pressure; it can make a mess if you are not careful.
 
I will replace the thermostats with 170's then. I did open the Oberg filter today, and had at least a half a teaspoon full of smal black particulates, like black sandy stuff. I cleaned that out. I also removed the in line fuel filter, and it was surely restricted when I blew thru it. Replaced it as well. Took the boat for a sea-trial. Still had trouble building power. It builds power slowly, but if I give it too much throttle too soon, it backs down. It makes an aweful lot of noise too. But that may be becuase I have the engine hatch open while running. My hatch lifter is bad, so I have it propped up on a 2X6. Could this be a fuel pump issue? How do I test that? MakoMark mentioned hooking up a fuel pressure guage. Is that available at like Autozone or ? If so, explain how to test the pressure. Also, could this be an ignition problem? By the way, thanks for all the help and input guys.
 
Ignition - maybe, but I'd be inclined to rule out fuel.

Gauge @ AZ; - yes, some will even 'rent/lend' depending upon where you are. Use is like a tire pressure gauge but one threads the gauge to the schrader valve. You need to take pressure readings, engine under load, with varying RPMs, up to WOT. If the pump doesn't delivery spec pressure across the entire load curve (rpms changing); something needs more attention.
 
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