View Full Version : Engine problem...please help

06-16-2008, 12:29 PM
My boat only starts when the engine has been cooled off. It won't start up after it's been running for a while. Could their be an issue with the fuel pump? If so, is it something I can do myself?

06-16-2008, 01:23 PM
Need more info. Year of boat, engine,etc. Does crank and not fire-off, or totally dead?

06-16-2008, 01:26 PM
sounds like vapor lock from the little you said about it. Explain a little more, could be a number of things though.

06-16-2008, 01:34 PM
Sorry...it's a 2003 X9 (209) w/Indmar Predator engine. I've heard from a few people about the potential "vapor lock" issue.

06-16-2008, 02:10 PM
its possibly vapor lock or potentially some sort of ignition/timing issiue ?? i had similar problem which turned out to be a fine hairline crack in the distributer cap !! new cap sorted it out ,

how long does it lie up before it will start again ??

06-16-2008, 02:13 PM
If it sits for about 30-60 minutes, it usually fires back up. I'm contemplating taking it in for service/diagnostic, but I'm afraid it's going to be expensive.

06-16-2008, 03:23 PM
30-60 minutes seems like a long time for it to be vapor lock, not to mention the fact that vapor lock in a fuel injected engine is typically uncommon because the fuel system is pressurized pretty far beyond the typical vapor pressure of gasoline, even in a heat-soaked engine on a hot day.

It would be fairly easy and potentially diagnostic to insulate your fuel lines in case it is vapor lock. There is a variety of such insulating material out there.

IMHO, more likely it's a fuel pump issue. The in-tank fuel pump in your boat has a history of being problematic. It's discussed here a lot, but the concept is that the fuel filter becomes plugged (it's located before the actual pump) and prevents fuel from being pumped in sufficient flow to cool the pump, the impeller fries, and you're out of business. If your fuel pump impeller is only partially fried, it may not be able to generate sufficient pressure to overcome vapor lock in a hot engine to allow it to start. You should be able to check the fuel pressure with a fuel pressure gauge at the Schrader valve on your fuel rail.

New fuel pump is about $500.

06-16-2008, 03:48 PM
What should the pressure be?

06-16-2008, 04:52 PM
What should the pressure be?Uh...I don't know. I've heard as much as 30 and as little as 12. JimNn might know, and certainly EngineNut would. If I were faced with the question as you are, I'd call Indmar. Reportedly, they tend to be pretty helpful.

06-16-2008, 05:04 PM
On mine, different motor though, on the rails it around 40psi.

06-16-2008, 05:25 PM
On mine, different motor though, on the rails it around 40psi.

Yes, typical fuel rail pressure is three bar (43.5 psi) on the majority of fuel injected motors. Some if not all gen III GM motors, which I believe the 6.0L vortec is, is actually four bar (58 psi).

For what its worth.

06-16-2008, 07:04 PM
Why does anyone think it's vapor lock? The pump is in the tank. The fuel is being pushed to the motor. That eliminates vapor lock and that's why they use that system.

Next time, leave the motor box open after shutting it down. What is the air
temperature when this happens? If it 's really hot, it could be a heat soak issue.

Just for grins, crack the throttle a bit when you try to start it and this happens.

Your flame arrestor is clean, right?

Look around the motor for loose wires and plugs. high temperatures can make cables relax and hang differently, which can break contact. If it cranks but doesn't fire (which hasn't been indicated yet), there are several things that can cause it.

06-16-2008, 08:46 PM
If it cranks but doesn't fire (which hasn't been indicated yet), there are several things that can cause it.

It does crank over but doesn't fire. After talking with a few people and visiting other forums today, most say it's not vapor lock on this type of engine. I went out in the garage and turned the key and it fired right up. This is the most frustrating part about it. The damn boat starts in the driveway but won't on the water. Not good. :(:(

06-16-2008, 08:59 PM
Do you have access to a timing light? Take it out with you next time and if it doesn't fire, put the timing light on one or more plug wires and see if you have spark.

06-19-2008, 10:17 AM
hi chrisg , your problem sounds very similar to the problems i had 2 seasons ago , i replaced the cap and rotor but had the same issue few weeks later , i then replaced the ignition module and havent looked back since , i understand your frustrations as it drove me mad for weeks too normally less frustrating when the damn thing doesnt start at all lol....best of luck.

06-26-2008, 09:53 AM
Quick update on my starting issue...basically there is no update. I dropped the boat off for service over a week ago and just like Murphy's Law, they aren't seeing the issue. They started the boat up and ran it for a while and sure enough, it fired right back up. According to the diagnostic, everything came back fine. They told me the other day if the starting problem doesn't occur at the shop, they'll have to take it to the water and test it there, apparently under a load. I'm getting very frustrated and don't want to spend $500 just on troubleshooting. Does it make sense at this point to have them replace the starter solenoid if they can't find anything wrong?

06-26-2008, 10:23 AM
If they're not taking it out on the water, it's not going to show up. You didn't notice the problem after running it on the trailer for an hour and neither will they.

Did you open the throttle a bit (that's what I meant by "crack the throttle")?

If you can, get the boat, take it out and make the problem occur again. If you have a timing light and multi-meter, some wrenches and screwdrivers and maybe a test light, you should be able to find the source of the problem. Using a diagnostic computer is great if that's where the problem lies but this probably doesn't.

The second thing you can do to find it is a wiggle test of any wires that go to the injectors, fuel pump, ECM, sensors, distributor, ignition switch and safety switch.

If you have a meter and can get it to not fire:

Remove the flame arrestor and crank it. Look for fuel spraying out of the injectors. Is it spraying? If yes, it's a spark issue. If not, turn the key to ON and listen for buzzing that lasts for two seconds. If this doesn't happen, something between the ECM and fuel pump isn't completing the circuit. There's a green/white wire that goes to the fuel pump (FP) relay and this should show a ground contact when the ECM tells it to latch. There's a red wire at pins 30 and 85 that should be hot all the time,with a fuse inline. That's an easy one to test. If no voltage on either, it's not going to start. If the voltage is present on these two but not on 87a when the relay latches, it's a bad relay or plug. If all voltages are correct, check for continuity from pin 87a on the relay to the fuel pump. If that's OK, check the fuel pump's ground lead.

I didn't see which motor you have but if it's TBI, look at the 4 wire plug at the distributor for a purple/white wire. Measure the DC voltage- should be 1-2VDC. If you get nothing you may have a bad IC (Ignition Control) Module.

If your tech actually sees the problem, he should be able to find the source. MC actually has a class for this kind of thing called "On-water Advanced Diagnostics" and the instructors use past experience to cause the motors to crank but not fire. There are some really weird problems that have come up and if your tech has been to this class, he should be able to find it quickly.

06-26-2008, 11:02 AM
See also: http://www.tmcowners.com/teamtalk/showthread.php?t=17522. It might be of some value.

06-26-2008, 11:49 AM
My boat only starts when the engine has been cooled off. It won't start up after it's been running for a while. Could their be an issue with the fuel pump? If so, is it something I can do myself?
Sounds more like electrical problem. Begin by pulling a plug wire and ground it to the block with a screw driver. Leave a little gap to see if there is spark. If your brave just hold onto the screw driver when stuck in the plug wire. If you have spark, then it's a fuel problem. If not, check your coil. Often an internal wire in a coil can break leaving a gap when hot and closing together when cold. As long as the engine is running, current will jump the gap, but not at low starting speed. The other thing may be your ecm. Same kind of story as the coil. But first narrow it down to fuel or electrical. Good luck

06-26-2008, 11:49 AM
ChrisG- I just looked at your location- have you been boating when it was really hot? If that's the case, and I have seen extremely high temperatures out there, JesusFreak's link is a good one. It could definitely be a heat soak issue and your ECM doesn't have the "high temperature" calibration that they use in places like AZ, etc. Call MC and ask if they have one for your ECM. If this is actually a heat soak issue and they don't have a high temp program, you can either turn the blower on more than 5 minutes before starting (you should be doing this anyway) or open the motor box a few minutes before cranking to let the motor cool down.

If it is extreme heat soak, the tech should have seen an overheat indication when they connected it to the computer. If they only used a scan tool, they need to get in the game- I'm not aware of a scan tool that shows overheats and in order for them to see the checksum and some other info, they have to use a diagnostic computer, either a Tech I or PC.

I edited my posts because I thought the boat was older, but the info still applies after edits. The crank position sensor may be at fault and could definitely keep it from starting but while I was working on these, I never had a failure of that part. Doesn't mean it can't be the cause this time, though.

06-26-2008, 11:52 AM
Does your engine have a crankshaft position sensor? If so, the symptoms you describe sound like it is failing.

06-26-2008, 12:15 PM
Thank you very much for all your responses. I must say that I'm not very technically inclined when it comes to these troubleshooting options. Aren't all these you guys have mentioned something a certified MC tech should know about? Heck, they're charging me $120 an hour. Anyhow, at least I can bounce these ideas off of them (and I look a little smarter :-). I'll post again when I get an update. Thanks again everybody.

06-26-2008, 01:31 PM
For $120/hr he better be trained and well able to find this fast. Intermittent notwithstanding, if it doesn't want to start, it's possible to find it. Once it wants to start, it's back to 'wait-n-see' until it won't start again. Still, most of the tests can be done in 5 minutes if they have all of the tools handy.

07-14-2008, 12:59 AM
Got the boat back last week from the dealer. They charged me $240 (2 hrs) to tell me they couldn't find anything wrong with it. They told me it fired up up everytime they ran it for 20 to 30 minutes. The diagnostic test came back negative. I took it to the lake this past week and sure enough, after taking a few runs, it wouldn't start back up. After it sat for about 45 minutes, it would finally fire back up. At this point, I don't know what to do. After reading through many of the threads here, I decided to pull out the in-tank fuel pump. I'm going to replace it with a new one and hope (key word) this solves the problem.

I took a few pictures and was hoping anyone knew what I needed to actually replace. The first pix is the plastic housing where the pump sits (inside the tank). The second pix is the metal plate that attaches to the housing. My question is, should these both be replaced and also, what is the circular donut looking thing (marked with a P) on top connected to one of the fuel lines? Any help here would be greatly appreciated.

By the way, does anyone have an idea where I can find this fuel pump set up other than the dealer? I called an outfit (Carter distributor) and they told me I could only get this thru MC. Thanks again.

07-14-2008, 08:59 AM
Someone just posted the part number for an alternative to the OEM pump in another thread but before you do anything that costs you more money, look at the photo of the pump that you posted. Next to the clamp at the upper right, feel the rigid fuel line where it makes a tight bend. If you think of what happens to a soda straw when you bend it, the same kind of kink could happen to the Teflon line and if that one is the supply, it will restrict the flow. See if you can remove the sharp bend. If it is the cause, I would contact MC and the dealer about it because there should be no kinks in the fuel line, especially coming from the factory.

07-14-2008, 02:01 PM
For some reason I do not think that this is a fuel pump issue. Vapor lock is not an issue due to the fuel system design.

A few of the board members recommended replacing the distributor cap. This is a simple inexpensive procedure.

Did you check the spark plugs to see if they need replacing? Of course, if you go through the effort to check them, I would just replace them.

Knock out all of the things that you can to narrow your list of possibilities.

The thing with the "P" on it is the fuel pressure regulator.

Did the dealer actually get your boat on the water? If not, I would arrange to have a tech go for a ride with you. You paid money to have your boat fixed and they did not fix it. If your dealer is a good one then he should be willing to work with you. Of course, if you get a tech to ride with you, guess when the first time the boat will work perfectly will be?