Starting problems

[namlek]

2001 Challenger 2000 240 hp

Kept in a "quick launch." Boat starts when they put it in the water to take it to fuel dock. I get there half an hour later and it just won't "catch". Did manage to get it going after 20 minutes of trying and take it out for an hour or two, runs fine, and starts right back up to "flush" cooling system.

Next day go through same thing all over again. Mechanic thought it was the starter, which I replaced. Didn't solve a thing and most recently it stopped "cranking" at all after trying for about 10 minutes even though there was still plenty of battery left.

When it does "crank" sounds like it's not getting fuel. Not sure what to try next?

Thanks for any suggestions. Btw I read an article on the new "Scarab" Jets and it said the design was supposed to be the new Sea Doo Boat just before they decided to discontinue.
Kel

 

[Sportster-2001-951C-Stock]

If the cranking is weak, there may not be enough voltage remaining for the electronics. Aftermarket starters often are not a good quality and don't provide the torque necessary to properly spin these motors, always best to use an original equipment starter or rebuild the original.

That said, if the motor is spinning well but not catching then either fuel or spark are insufficient in some way, low fuel pressure can be caused by a number of things relating to the fuel pump, the fuel pressure should be checked.

Ignition spark also is necessary of course, and fairly easy to confirm by using an ignition spark checker.

It's possible there may be an electrical issue with firing the fuel injectors, a NOID light can be used to confirm the injectors are being fired by the computer.

If you have a leaky fuel injector, it may be dribbling fuel into the cylinder and flooding that cylinder making it hard to start. There is a procedure for checking for leaky fuel injectors in the BRP factory service manual.

If the cylinders should become fuel flooded for some reason, they can be cleared out by using "flooded mode". The flooded cylinders are cleared out by placing the throttle in full open position and cranking the engine over using the starter, this full throttle position tells the computer to not fire the fuel injectors while cranking. By doing this, the excess fuel in the cylinders causing a "no start" condition is pushed out through the exhaust system and once the fuel is mostly gone the engine will begin to catch and fire. If the throttle remains in full open position the engine will not have further fuel added while cranking. This is how you can determine if the engine was fuel flooded.

If the engine is not getting fuel as you suspect, listen carefully for the sound of the electric fuel pump, which should run for a few seconds as you place the lanyard key onto the lanyard post. This cycle takes a minute or two with the lanyard off the post before it can be repeated. The sequence goes like this: Before the engine is cranked, the electric fuel pump needs to run in order to pressurize the fuel injector fuel rail with fuel. Thus, the computer is supposed to energize the electric fuel pump as you place the lanyard on the lanyard post in preparation for the startup.

Regardless, the fuel injector rail needs to be pressurized else the fuel injectors will not shoot pressuruzed fuel into the cylinders during cranking. Fuel pressure can be verified by connecting a fuel pressure test gauge to the fuel rail.

Hopefully I gave you some helpful ideas for things to look for......

 

[TEXAN]

I had a similar issue last year. It was directly related to bad battery. Wasn't giving off enough cranking amps/volts. Replaced with a marine cranking battery, pretty much worked flawless afterwards. I believe Dr. Honda has a thread about recommend batteries which is where I got the idea.

Tex

 

[namlek]

You certainly gave me a lot!! Thanks very much. Question about "starting when flooded".My boat has a dual control set up which I don't think allows me to adjust throttle when in neutral, which is where it has to be to start. I don't believe I'm able to increase throttle unless boat is in forward or reverse. I'll check my manual to see if there is a recommended procedure for starting when flooded. Thanks again.

 

[namlek]

Thanks much. Battery's good. Btw I said it wouldn't crank anymore after trying for about ten minutes. Found out yesterday I burnt out the new starter trying to start the boat. He pulled it out for repair and it should be back on now. My fear, of course, is that he'll put the starter back in, it'll start up and he'll call me and say it's good to go, which of course it won't be. I'm afraid I'll have to pull boat out and take it to a dealer. I really love the "jet" and think its a great way to go here in "shallow" SW Florida, but it's getting real tough to find anybody to work on them. It's a shame. Thanks again for the suggestions.

 

[Sportster-2001-951C-Stock]

Also a difficult restart might be caused by a failing throttle position sensor, that's pretty common acctually and much more likely than a leaky fuel injector.

Regardless, by applying some amount of throttle while cranking the engine might start easier and if so, have the mechanic test and/or replace the throttle position sensors as those are getting pretty old by now anyway and should be replaced.

 

[Coastiejoe]

And,, boats MUST have the blower going for 5 minutes or so to get some god oxygen into the hull for the engine. Many open the rear engine hatch itself. It is VERY common to run fine but not restart after turning it off and sitting a bit. It NEEDS air. Plus,,, it is a safty concern to clear any fuel fumes to prevent serious injury or worse...

 

[Sportster-2001-951C-Stock]

Good point Coastie, the OP should also try running the blower to see if clearing the bilge of potentially fowl air helps. Fowl air can make it had to start as well, fowl from steamy-moist air (causing wet ignition) to a slight exhaust leak into the bilge (lack of oxygen).

My personal feeling is the MPEM senses the throttle is partially open despite it isn't, due to a defective throttle position sensor and thus is fueling improperly based on the erroneous feedback.

 

[namlek]

Thanks very much. One of the problems of being "trapped" in a quick launch is that boats don't get "serviced", only "fixed" when they break. I plan on pulling it out of the water soon and bringing it to a dealer and have them go through it and replace items as necessary. Thanks again. I'll keep you posted.

 

[namlek]

Thanks all. Boat is starting after rebuilding starter (again) and "adjusting" idle control. I still think the boat smokes more than it should (even for a two stroke) but I can handle explaining to people once in awhile that my boat isn't on fire! Thanks again.

 

[Sportster-2001-951C-Stock]

Oops my bad, all this time I thought we were discussing a 4-stroke Rotax, didn't realize it's a mercury sport jet....

2-strokes smoking tells you it's receiving lubricant, remember the nature of these is ALL of the lubricant is lost to the exhaust system. Also, a cold engine before reaching full combustion temperature will tend to not "burn" the oil into it's finer (less visible) constituents. Does it still smoke profusely at low speed after a ride at half speed or more across the lake?

That said, if it seems too much smoke and thus the oil consumption is excessive, it will tend to foul spark plugs rather often, excess lubricant will cause hard starting due to oil-fouled spark plugs as well.

Could be as you suspect, there's too much lubricant. If so, the likely cause is the oil injection system linkage might be maladjusted. There are a couple of alignment marks (lines) marked on the moving oil control linkage that should become parallel and line up while the throttle is at idle position. If these lines are in alignment at minimum throttle position, the adjustment is most likely correct (I've forgotten actually if the marks are supposed to align at full throttle position, but I don't think that's the case).

BTW, a 2-stroke engine is quite prone to spark plug fouling and this is often the cause of hard starting and/or poor performance. You should keep a spare set of known good (new) spark plugs on board and familiarize yourself with the process of changing them. Also, it's often possible to clean them s well, I clean mine with carburetor cleaner and run them but if they foul again quickly I throw them away.

 

[namlek]

Thanks so much. I read somewhere about aligning "marks" on the oil pump or on the injection mechanism and should probably go looking for it. You only seem to notice the smoke when you first start it and at idle. I remember the "2-stroke fouling plugs deal" from my dirt bike days (about a thousand years ago !) and do keep a set on the boat and change them at least a couple of times a season. Thanks again for the help.

 

[Sportster-2001-951C-Stock]

You only seem to notice the smoke when you first start it and at idle. I remember the "2-stroke fouling plugs deal" from my dirt bike days (about a thousand years ago !) and do keep a set on the boat and change them at least a couple of times a season. Thanks again for the help.

This sounds pretty normal.

Also, some of those with electronic oil injection control used the engine temperature sensor to determine how much oil is necessary. Thus, colder temps produced more oil as well and if the temp sensor was defective the electronic oil injection would be providing oil at a high rate under the assumption the temperature is very low. I'm not sure if our engine uses this feature, it may be later engines.

Anyway, if it won't start try opening the throttle as we discussed earlier(push the button on the shifter or pull shifter out, away from it's axis, to allow throttle in neutral) and if that doesn't help it might be necessary to swap spark plugs. Read the section of your owners manual for instructions of how to use the throttle by pushing the button or pulling the lever away from it's axis, by doing this you can increase engine speed while in neutral and allow more air during cranking.

Also a hard start on some of the models was caused by a defective engine temperature sensor, the computer thinks the engine is very cold and thus applies too much fuel enrichment. In the case of mild flooding, opening the throttle some amount allows more air and can compensate for some amount of excess fuel. Could be your engine temperature sensor is defective, that's pretty common on some Optimax EFI models....

I think you can get her to fire off by opening the throttle some amount during cranking, maybe 30~40% is enough for some extra air.

 

[namlek]

First I realize I'm replying to a very old post, but I can't help myself. They are telling me that I need to replace "throttle positioning sensor" and that it costs almost $700 for the part. I noticed in your post that you revered to "sensor(s)".Is there more than one? At $700 a piece I'm hoping not! Thanks very much.

 

[Coastiejoe]

First I realize I'm replying to a very old post, but I can't help myself. They are telling me that I need to replace "throttle positioning sensor" and that it costs almost $700 for the part. I noticed in your post that you revered to "sensor(s)".Is there more than one? At $700 a piece I'm hoping not! Thanks very much.

The TPS is one of the most expensive parts on the engine. I would ask them to PROVE to you that it is not working or out of range. This can be done easily via a Candoo Pro which you can buy from $395. The dealer also "should" have a Budds system.

 

[Sportster-2001-951C-Stock]

Candoo Pro isn't for Mercury Sportjet. What are the symptoms? I still recommend opening the throttle 1/3~1/2 while cold-starting these engines, then reduce speed quickly once it fires.

What is the serial number on the plastic cover on top of the engine?