27 replies to this topic

[rodder77]

Need some ideas on what could be wrong? Put the boat in this season a week or so ago, filled the remainder of the tank with new fresh premium fuel and added some Seafoam. Took the boat out to run off the full tank of gas. Ran fine for about an hour then top speed gradually began to drop from 50, to 45..40...35....30...25 and continue to bog down. Turned around and headed back to the marina. Replaced all the fuel filters, in-line, water filter and took apart the VST and cleaned the final filter (looked really pretty clean) as well as the filter in the tank - on the end of the fuel pick up. Replaced the booster/primer pump near the in-line filter, as I had a new one on hand and checked the tank vent hose (to eliminate the possibility of a vacuum in the tank). Checked the prop and intake grate for obstructions and the mechanical functions of the throttle. Now it won't start unless I use starting fluid and it will not continue to run unless I continue to spraying the fluid (UGH). in addition, I took a remote gas can of fresh gas and ran it directly through the primer pump (through the inline filter) to rule out bad gas in the tank and everything pre the pump and in-line filter. My family and I would be greatly appreciate and ideas!!!

Thoughts?

[igneous]

Is you battery fully charged? I should be since you ran it for an hr. These fuel inj. engines need good charge to run right. You may want to look at fuel delivery...elect., lift and high pressure pumps.

[rodder77]

Battery is fully charged - it was also on a battery tender for the winter. When I launched the boat for the first time of the season it was right around 12.7 -12.8 volts, and ran fine for about that hour or so before the symptoms started. Even after getting it running for short period of time (as not to dry out the cylinders) with starting fuid it is still showing 12.7 volts at the battery. Took it to a Merc dealer last night.....their thought was maybe the injectors? I'm sure the labor is going to kill me whatever they (hopefully) find is the cause. I honestly believe it was that darn Seafoam....... my new motto is "if it not broken don't fix it".

[mikea]

I've used Seafoam and never had a problem. If any of the fuel injectors are plugged the result would be as you wrote, but - with these efi controlled engines, so would a bad sensor (air temp, throttle control, etc).
There are a couple of fuel pumps also. One is high pressure and one isn't. Checking the high pressure pump is relatively easy, and I'd check that before doing the fuel injectors.
The way that you described the event, it sounds like everything started off good, but then went bad while continuing to drive. Did the rpm drop with the top end speed, or did it mantain the rpm and the speed just contimnue to decrease? Over how long, a short while(minutes) or really fast (seconds)?
Good Luck - hopefully, cleaning the fuel injectors will fix the problem. It surely can't hurt anything - except your wallet.

[rodder77]

The shop is going to check the high and low pumps first. You are correct everything started off fine driving for a while and then the speed started to drop right along with the RPMs,acted like it was starving for fuel. It took place over a period of time, say 30 minutes. That is what makes me think it is something that the seafoam started to break loose (varnish, etc) and it kept building up someplace (?), getting progressively worse. I gave the shop the rebuild kit i had for the pulse fuel pump (i just haven't gotten around to rebuilding it yet). While I was changing out the filters I also changed the temp. sensor on the port side of the engine. no change - If they hit my wallet to hard I will have to sit in the boat while its on the trailer with a hose spraying on me because I can't afford gas. Thanks, I will let you know the outcome either way.

[mikea]

Rodder77 - any update on what the cause was?

[rodder77]

no good update yet - apparently the high pressure fuel pump in the VST tank was bad (it was a replacement VST tank I put on from a newer boat). This is what the dealer said is the cause of the non-start problem. New pump just came in and they will replace it in the VST tank, this "should" resolve the no start issue, but still leave me with the original issue of the complete loss of power, speed and rpms. Dealer still thinks it is still fuel related (I would have to agree from what I see) and could most likely be the injectors which would need to be serviced ..UGH $ by pulling the powerhead out and cleaning/rebuilding the injectors. There are a few places online that will rebuild, clean and match the injectors for around $150 and next day air them back. So again I am just wating (on land, very dry and depressed) to hear from the merc dealer on replacement of the fuel pump, getting it started....and next steps.

[rodder77]

Well, got the back - merc dealer got it running put in a new high pressure fuel pump, rebuilt the low pressure pulse pump, checked compression (all 125-135, good to hear) spark on all cylinders. Volt meter showing good charge while running 14.4v., checked the filter in the tank on the fuel sender one more time - it was pristine, put it in the water on Saturday, started right up and sounded great. Idled out of the marina gave it some gas and......... chug chug chug, engine would not run higher than a fast idle (5-10 mph). The longer we idled around 30-40 min thinking it could clear itself up, the slower the rpms and speed would get. So my initial problem is still present.

Anyone have a similar problem or an idea on what else could be the problem (merc dealer still thinks it's dirty injectors- and want to pull the engine)? With the condition of all of the fuel filters were in (very very clean - near new looking) it is hard to believe that any amount of dirt would have made its way to the injectors...let alone all of them IMO. Could it be the TPS? does anyone have experience with a bad one? Anythoughts on a bad rev limiter (what are the symptoms) even though it still sounds like it is a fuel issue and simply starving for fuel and getting more plugged up as the engine runs.

Please help!!

[mikea]

Rodder,
These EFI engines are very dependent on good incoming data from the sensors.
You mentioned that you changed the head temp sensor on the port side with no change, but did you also change the coolent temp sender on the starboard side? If you have a Mercury Service Manual, page 3D-23 tells you all about the semsor interaction with the ECM.
I think that is where your trouble lies.
I had a similar issue and I found out that the Engine Control Module will go into a "safe operating mode", if the sensors are not sending good info to it.
Last year I changed the air temp sensor, the head temp sensor, and the coolent temp sensor - and it allowed the Control Module to operate normally again.

[rodder77]

Thanks! that sounds like what could be happeining!! As you said I did replaced the head temp sensor part # 13536A14 (port side on the head), however the only other sensor I see listed is on the starbord side part # 974651 (~$58), it too looks like another head temp sensor (has one connector wire coming out of it). I don't see an air temp or coolant temp sensor part or part # listed anywhere? Do you happen to know the part numbers for the air temp sensor and the coolant temp sensor? I really appreciate the help!! I have been looking at www.mercruiserparts.com

[rodder77]

I believe I located the correct parts (and #'s) - one is the starbord side temp sensor #974651 and the other is the air temp sensor on the manifold # 13221a1 or new # 13221T01. Just ordered them both! ~ $100 for both - hopefully one of those is the culprit!!!! (if not it can't hurt to have new ones on and it's cheap enough)

thanks!I

[mikea]

The part #'s match what I ordered. The air temp sensor is suppose to manage fuel flow (leaner or richer) based on the manifold air temperature. The starboard side is called a temp sender and has just one wire, where as the port side temp head sensor has 3 wires.
Good Luck and let us know if these fix the problem.

[mikea]

Rodder,
I reviewed the wiring diagram in the service manual and confirmed that the head temp sensor and the TPS inputs to the 82403 ECM are connected. That makes sense because they would adjust the fuel mix based on engine head temp and speed together in order to make teh right mix of fuel/air. The starboard side temp sender is sending data to the Ignition Control Module. That is a small black rectangular box mounted with 3 long screws holding it on top of another one that looks the same.

My troubles last year were 1) smoking at start up, and hard starting plus 2) engine stuck in safe mode.
The air temp sensor tested bad - it was 50 degrees outside, and the thing said it ws 90 degrees - that caused the engine to think it was hot when it really wasn't. I replaced the port side head temp sensor at that time also, but in hind sight probably didn't actually need to.

The engine stuck in safe operating mode - couldn't go faster than 25-30mph at WOT. That problem was resolved when I installed a new temp sender (starboard side). I had started with replacing the ignition control module #85716972 @$159 - thinking that it HAD to be the culprit. The problem continued to exist until out of frustration, I swapped the temp sender - and the darn thing returned to full operating mode.

According to the wiring diagram, the data flows between the ignition control module, the rest of the electrical devices (stator, trigger, CDM's voltage regulators) and the 82403 ECM. The air temp, head temp, and throttle position sensors send data to the 82403 ECM - which together make the engine run.

Your problem no longer seems to be about starting up, or even idling - it is when you try to accelerate. The funny thing is that some of the sensors data doesn't seem to matter at WOT, but getting it to run between idle and wide open depends on the darn sensors and control modules to work properly.

I am hoping that is your problem - but, if not I suppose it might be the TPS or the ignition control module. Hard to tell if they don't have the engine diagnostic computer. The TPS is easy to check - it is held on by 2 screws and be checked using a volt/ohm meter for continuity. It is really nothing more than a rotating variable resistor. I read that they do get worn out in spots over time - but, that doesn't sound like what is happening on yours. Yours seems more like the computer is deciding not to let the engine get the correct spark/fuel/air mixture - for anything other than idle.

Good Luck

[rodder77]

What are your thoughts about the rev limiter limiting retarding the rpms? that would be about my last option. I may have to break down and take it to another dealer, beacuse i really think it is fuel related due to the sea foam. It was running fine when we went out and then it slowly started to die. I called another merc dealer and he thought it was the statror high end windings (highly doubted all the injecors would clog with the fuel running through 3 filter prior to the injectors), however as I looked through the service manual it shows the cousin of the 240, the 210 having a high and low winding, however the 240 only has a single winding so it is all or nothing. Any thoughts on anything else mechanical -fuel flow related that could casue the fuel to be restriction after the high pressure pump?

I thought about the TPS too but the service manual indicates is does not effect WOT but instead works with the idle through the WOT, i can't even get to WOT and if i do it's about 10mph (at about 75% throttle) if i go to full, it dies. If the sensors don't change anything i may have the dealer check the TPS and whatever else they can think of. I hate loosing all of this time during the season on dry land. I appeciate the ideas and input you have had.

[rodder77]

based on your experince do you think ot could be the ignition controller you mentioned that you replaced 857169t2? they run about $260-275 new. ebay has a used one for $130. Ohterwise i am back to something physical resulting from the seafoam.

[mikea]

Rodder,
The fact that you can idle but not accelerate at all, plus that you have had the fuel pumps checks, still leads me to believe the problem is electronic related. Make sure the mechanic is using a diagnostic device to check the engine sensors both with key on not running and while running.
I had to swap out my TPS also, and I was pretty sure that it wasn't working because when I checked it using the computer it didn't read out what the manual said it should. I read lower, but not the correct values. I had bought a used one from a guy parting out for alot less than new price - and it fixed my problem immediately.
The thing with these EFI engines is that when you find the thing that is broke and replace the part - it immediately resolves the issue. You shouldn't need to float around and wait for anything to suddenly change to fix the problem.
As for the Ignition control module and the Stator idea - All of the rest of the electronic parts (Stator, Trigger, etc) can be tested to check if they are within allowable working specifications. That doesn't necessarily mean that they are good or bad - but in most cases will give an indication as to if they are working at all.
The thing is that your boat starts and it idles - so I am hesitant to say that the Stator or Trigger. I would think that if it was either of those, the engine wouldn't idle without noticeable side affects.
The only other sensor that might cause the issue is the MAP sensor, and that one isn't serviceable because it is on the main ECM box - the diagontis tool (computer) should be able to tell you if that is working or not.
It pulls data by sucking air via a small vacuum tube connected between the ECM box and the Manifold. They tell you to check it for cracks and that it is connected. That sensor does control the amount of air in the mix, and it is a very important sensor. Make sure that one is tested also.
The way you described the original event (slowing down over a time period) doesn't make me think the ignition control module is the problem, because I 've found that control modules either work or the they don't work. They do not usually go from working to not working a little bit at a time with those. It is all or nothing.
At this point, I would start by going through all of the trouble shooting tests that are listed in the books - startig with the electronic ignition.
If you take it to another mechanic, make sure they have a computer that can connect to the Mercury outboard with the 82403 ECM.

[rodder77]

well....recieved both sensors and the rev limiter (all new) put them on today and started the boat on the trailer (hose hooked up). Ran great, also did the "no no" of putting it in gear and reving it up briefly to see if it would rev past idle. It reved up perfectly! Put it in the water, strarted right up, idled great but still will not run anyfaster than idle in the water? moving the throttle forward still results in the original issue, it just boggs down.

Pulled the boat out, again checked the the intake for obstuctions as well as looked through the rear nozzel. Looked fine no obstructions. Ran it again on the hose, to flush it out, ran fine and again would rev up perfectly past idle on the hose?

thoughts?

[mikea]

Runs on the trailer with hose hooked up, but not in the water. I read a forum posting with a very similar situation, but I cannot recall what the solution ended up being. I will try to locate that posting.
This has got to be very frustrating for you by now.
A very long shot - Have you checked the exhaust hoses for delamination?
If it runs on the trailer, what is different about it being on the water?

[rodder77]

Frustrating is the nice way to put it at the very least. Summer is half over and I had the boat out once. I was thinking along the same lines as you, so Idid check the exhaust hoses running off the expansion chamber to the mufflers (with boat not running) when I replaced the sensors. They looked fine. My only thought..again may be a a very, very long shot is maybe one of the exhaust hoses has an exhaust leak into the closed-engine compartment when the boat is on the water running? On the trailer when it seems to run fine the sun deck is open with the hose attached allowing air to circulate freely. At this point I would try just about anything. (It was something progressive that caused the issue initially since we were running the boat for an hour as it was slowly begining to slow down, not like it was a catastrophic mechanical failure). The only difference I have read from any of the forums is that in the water the engine is under a "load", as compared to an idle on land which requires very little fuel with no impeller resistance from the water.

[mikea]

I feel the pain, last summer was a complete loss for me trying to figure out why my Challenger 2000 wouldn't run. That was not much fun at all.
Being in the water does put a load due to the jet pump wanting to push water through it, vs sitting out of the water with the hose under normal water pressure. I cannot recall if you had the cylinder pressure checked, but that seems like a good place to check.
Due to the way the failure occurred (slowly, during a long ride), it does seem like when the throttle asks for more speed and the engine chugs - it almost sounds like one of 2 things could be happening.
1) something is binding up - perhaps a bearing in the jet drive?
2) the fuel/air/spark mix during detonation isn't able to change as is needed, when accelerating.
I think there is a section in the manual that will give step by step instructions for checking the jet pump.
The second one can be trickier because of the electronics, but with that one I'd start with compression. You have already checked fuel pumps, and now the sensors have been replaced. The next thing to check would be the rest of the spark generating components. The stator, the trigger, the ignition control module, cdms, the plugs, the voltage regulators.
The manual has detailed instructions on how to test/check those, with a diagnostic tester.
If it idles fine (in and out of the water), I do not think the injectors are the problem. If they were plugged up, they wouldn't work in any condition. This has to do with something needed that controls or provides the right amount of spark, fuel, or air flow while accelerating. Has the diagnostics showed that the MAP sensor is working?