200EFI lack of power

[jtsailjt]

I recently purchased a used 2001 200EFI Saltwater series motor from a dealer and it doesn't seem to be putting out the power I think it should (and the dealer agrees) but we can't figure out why.

As background, the first owner of this motor bought it new in '05 and used it for diving/fishing so spent lots of hours each day at close to idle thrust for 4 seasons and then traded it in so the motor sat at the dealers for a year. The motor starts smoothly and seems to run OK, but trimmed out at WOT, goes about 5-7 mph less, and doesn't get up to the RPM's that other people with the same boat, prop, hp and gear ratio, motors get. Instead of about 5500RPM at WOT, I get 5100 when it's cold, but within just one or two minutes the motor warms up and the best it will do is about 4600RPM. It has new plugs and recently rebuilt fuel pump and timing, etc. has been adjusted and compression checks good.

I've been through the Quicksilver prop selector lots of times, as well as asked several owners of the same model boat, and the prop I currently have is conservatively pitched/sized, and one that everyone who has one says should give me a great hole shot and let the motor spin at least 5500RPM.

So, what could cause an EFI motor to lack about 15% of the power it should have at WOT, and also have noticeably less power when it's warm than when it was still cold?

 

[Faztbullet]

Re: 200EFI lack of power

Is it using a lot of fuel???

 

[jtsailjt]

Re: 200EFI lack of power

I'm not sure how much fuel it's using. My boat has a 50 gallon tank so it takes quite a while to empty it or to see it go down on the gauge. If I am using an abnormal amount of fuel, it's not something I've noticed. Why, whatcha thinkin?

 

[sxmerc]

Re: 200EFI lack of power

I thin where faztbullet is going with this, is that it may not be coming up to temp, or the thermo sensor is bad, and the PCM thinks the engine is still cold, and keeping the enigine running in warm up mode.

 

[jtsailjt]

Re: 200EFI lack of power

I thin where faztbullet is going with this, is that it may not be coming up to temp, or the thermo sensor is bad, and the PCM thinks the engine is still cold, and keeping the enigine running in warm up mode.

What's a PCM? And would this cause it to have less power overall, and to have less power when it's warm than when it's cold?

 

[jtsailjt]

Re: 200EFI lack of power

I thin where faztbullet is going with this, is that it may not be coming up to temp, or the thermo sensor is bad, and the PCM thinks the engine is still cold, and keeping the enigine running in warm up mode.

Is there a way to tell if the engine is still in warm up mode, or whether the PCM thinks it's warm or cold? Is that something that can only be determined by hooking it up to the analyzer or is there some way I can tell myself?

The dealers mechanic is telling me he thinks it might be partially clogged injectors, and wants me to run a few (50 gallon) tanks through it with injector cleaner mixed in. But I don't understand how, if it's an injector problem, it would run faster when cold than it does when hot.

 

[sxmerc]

Re: 200EFI lack of power

Easiest way to tell if you're not familiar with how hot it should get by touch, is to shoot the heads by the thermostats with a temp gun, after the motor has run for 10 or fifteen minutes. If it's not coming up to operating temp, the computer is going to increase injector pulse width, and essentially flood the engine. This is worsened at higher RPM's as fuel mixture and oil ratio are all ready elevated due to demand by the higher RPM. On a another note, I have never seen fuel injector cleaner additive actually clean a restricted injector. The only real way to get them clean is to remove them, and have them professionally cleaned, and checked. If the injectors are indeed restricted, you run a very real risk of doing severe mechanical damage to your engine by continuing to run it this way, especially at higher speeds. Once you start leaning out the fuel from a cylinder while it's running hard, that cylinder is going to start to get hot. The fuel charge to a cylinder actually helps cool that cylinder during normal combustion. There are other possibilities as to what the problem may be also. My suggestion... Let a repair shop take a look so as not to risk serious damage. Hope this helps.

 

[jtsailjt]

Re: 200EFI lack of power

Thanks SXMERC, My dealer has sent one of his mechanics to ride with me because I was complaining about the motor not running correctly, and he noticed the decrease in RPM once it warmed up too. He suggested running the fuel injector cleaner through it, but what you have to say about having them cleaned is very interesting and I think I will have that done soon, and I'm also going to stay away from any extended WOT to avoid overheating the cylinders until I get this sorted out.

As far as the engine not coming up to temperature, I'll get that checked too, but it seems to me that the evidence points to that not being the problem. The computer seems to be sensing it being warm because it is doing something that cuts back on the RPM's after a few minutes of hard running. My dealers mechanic says that when it's cold, the computer sends more fuel initially, until it gets warmed up, and then cuts back on the fuel to normal amounts. If everything is working normally, it doesn't negatively affect performance, but in this motors case, the computer sensing it being warmed up and decreasing the amount of fuel back to normal slows it down at WOT by about 500rpm. So, the problem seems to be a general lack of fuel to the cylinders and that's why the mechanic recommended the injector cleaner. Do you agree with that reasoning?

BTW, checked fuel pressure yesterday and it was 38psi at idle and increased slightly at higher rpm's so that is normal?

 

[sxmerc]

Re: 200EFI lack of power

He is correct as to how the computer governs fuel. As long as it's coming up to temp, then go forward from there. I'm just trying to send suggestions as to where to look having not actually seen the motor myself. Good luck!!

 

[jtsailjt]

Re: 200EFI lack of power

He is correct as to how the computer governs fuel. As long as it's coming up to temp, then go forward from there. I'm just trying to send suggestions as to where to look having not actually seen the motor myself. Good luck!!

...and I appreciate you trying to figure this one out! Do you agree that the fact that the WOT rpm is lower after a few minutes is an indicator that it's getting warmed up and the computer is sensing that it is? I don't want to take anything for granted but that seems to be the case. So, I guess I should get the injectors cleaned next? Is it possible that the stator is degraded or in the process of failing and is not acting correctly when it gets warmed up? I've got a friend who says that sometimes stators will test out normal, but when they get warm, don't work correctly. Not sure what the symptoms of that would be but right now I'm trying to think of things that would cause the rpms to decrease about 500rpm once the engine gets warmed up.

 

[sxmerc]

Re: 200EFI lack of power

The stator being the issue is possible, but I kind of think it's unlikely where you are only dropping 500 RPM. I think you are right in chasing a fuel issue. Are you able to hook up a fuel pressure gauge and see what the pressure does when the RPMs drop? Also, give the primer bulb a squeeze after the speed drops. You might have a fuel restriction. Couple more easy checks before you start yanking injectors.

 

[jtsailjt]

Re: 200EFI lack of power

The stator being the issue is possible, but I kind of think it's unlikely where you are only dropping 500 RPM. I think you are right in chasing a fuel issue. Are you able to hook up a fuel pressure gauge and see what the pressure does when the RPMs drop? Also, give the primer bulb a squeeze after the speed drops. You might have a fuel restriction. Couple more easy checks before you start yanking injectors.

Yesterday I put my boat back in the water and once again, about 5100rpm's at WOT, but decreasing quickly (within 2 minutes) to about 4600rpm's and until it cools off again, that's the best it will do. This time I had someone else to drive so was able to get back and check the primer and squeeze it. It seemed normal and squeezing it several times with the engine running at high rpm's seemed to have no effect on the way the engine was running. I don't have a fuel pressure gage of my own to check it at high rpm's but that might be possible if I can get my dealers mechanic to stop by to check it out again.

 

[jtsailjt]

Re: 200EFI lack of power

Just want to keep this updated in case somebody else has a similar problem. The latest is that I dropped off the boat at the mechanic after running lots of injector cleaner through it with no change, or very little change, with the exception of about a 10 minute period when suddenly it really came to life and had the power I've always thought it should have. But then, back to its doggy ways. So, I left it with the mechanic and he has determined that once the motor is warmed up, the whole left side is putting out very little power and he thinks it's due to a lack of fuel on that side only. He said it runs better when cold because the computer commands 40% more fuel in warmup mode, but once it's warm and that ends, it's not getting enough fuel in the 3 left cylinders to generate any power. He said that once it's warmed up, he removed all 3 left plug wires and the motor still sounds just the same as it did with them connected, but when he removes just one right plug wire, the engine suddenly starts running very rough.

So, he is going to remove the left fuel rail tomorrow to see if something is blocking it, and if that's not the case, he thinks it could have something to do with the ECM or the temp sensors. This is starting to get interesting, and I'm starting to be more hopeful that we'll soon get to the bottom of it.

 

[islandcruiser]

Re: 200EFI lack of power

It could also be a faulty shift switch. This switch cuts out 3 cylinders during a shift into gear.

 

[jtsailjt]

Re: 200EFI lack of power

It could also be a faulty shift switch. This switch cuts out 3 cylinders during a shift into gear.

Thanks for that, right now the mechanic is theorizing that my problem was partially clogged injector screens so he took off the fuel rails and blew them out along with the injectors. He says that he thinks that with partially clogged injectors, the lower injector in each pair had enough fuel to squirt close to what it normally would, but the upper injectors (left side of engine) wasn't getting enough fuel through to fire properly. It doesn't seem to me that is the likely cause, but he's the experienced mechanic, not me so I'm going with the flow, hoping he'll cure whatever ails it. I don't want to tell him to not do anything, even if it seems to me to be unlikely to fix the problem. He's supposed to put it back together and test it out tonight so I should hear from him tomorrow about it. If it's still not fixed, I'll be sure to mention your faulty shift switch suggestion. To me, since we discovered it's a left side problem, and he's measured the fuel pressure to be normal, it seems likely to me that the problem is an electrical one such as your suggestion. Fingers crossed, waiting for tomorrow. But even if it's fixed, now I have to travel out of town for the next 6 days so won't be able to try it out myself, but I'll update this again as soon as I hear news, yea or nay.

 

[jtsailjt]

Re: 200EFI lack of power

The stator being the issue is possible, but I kind of think it's unlikely where you are only dropping 500 RPM. I think you are right in chasing a fuel issue. Are you able to hook up a fuel pressure gauge and see what the pressure does when the RPMs drop? Also, give the primer bulb a squeeze after the speed drops. You might have a fuel restriction. Couple more easy checks before you start yanking injectors.

WE HAVE A WINNER!!! It was a fuel issue.

My mechanic removed the fuel rails and said it was very dirty in there. He sprayed some sort of cleaner on the injectors and blew out the very fine screens that are on the inlet end of them, and put it back together and my problems is FIXED!! They had me running a 15P aluminum prop and were telling me it was appropriate and yesterday when I tried it with that prop, I pulled the throttle back at 6800rpm!!! Switched to a 19P Mirage Plus and it now spins 5800rpm and goes 48mph (update: 44 knots on the GPS!), about 13 mph faster than it's been going all summer since I bought it!

Apparently there was so little fuel making it into the cylinders that the extra fuel the computer adds when it senses the engine is cold made a big difference, whereas normally you wouldn't even notice it. Before he cleaned it out, he said the left 3 cylinders were barely providing any power at all because the right cylinders were using up all the fuel when they fired so the left side was just limping along for the ride. Anyway, it was a fairly tough one to diagnose but the fix was relatively simple and inexpensive, with no new parts needed. I have an aluminum fuel tank and an inline cartridge filter as well as the normal cartridge filter in the engine, so hopefully my injectors will stay clean. At least now, if I have the same problem again, I'll know right where to look.

Thanks to all who attempted to brainstorm this for me. It's been frustrating because it took so long, but now I can really enjoy my boat. What a difference! It's much smoother sounding and jumps out of the hole (that's saying something for a 20' Grady!!!) and the top speed is almost 10mph faster than I've ever been in this boat!

 

[islandcruiser]

Re: 200EFI lack of power

Good to hear!! I'll try that with mine as well. Enjoy

 

[sxmerc]

Re: 200EFI lack of power

Great news!! Now go enjoy it!!