1998 dt200 efi bogging out

[Ebocaj]

Hi guys
Bought a second hand dt200 from a shop
Was told was all running good when removed from boat. Installed motor to my boat. Started first pop in tank ,everything seemed good,idiled and reved with no warning lights.
Put boat in water, took off good but would just bog out if you tried going any more than half throttle. After 2mins of running the oil flow warning went off.
Took boat back to my workshop and checked all oil lines, pump and flow sensor. Replaced flow sensor, bleed system and checked everything was to workshop manual.
Tested in tank,all ok. Put back in water , no oil light but still same problem.

Went through whole motor.
Low pressure and high pressure pumps all ok.
Replaced flywheel as magnets didn't look good.
Replaced all stator coils.
Replaced plugs
Replaced fuel and oil filters
Had injectors cleaned and flow tested
Def has spark on all 6
All plugs look to be burning the same.
Compression 108-115 psi

After all that ran in tank . Ran perfect idiled nice. Could rev right up no problems

Put boat back in water and still same the same problem. Can lay the power on nice and slow but once you get to half throttle just bogs out. No warning lights ect come up at all.

Am at a loss now don't know where to go from here
Any help much appreciated as I'm missing out on this season

Thanks

[Solarman]

Ok. You don't really get specific on what you did.

You said:
Went through whole motor.
Low pressure and high pressure pumps all ok.
Replaced flywheel as magnets didn't look good.
Replaced all stator coils.
Replaced plugs
Replaced fuel and oil filters
Had injectors cleaned and flow tested

I have to admit you have done quite a lot.
What on the low press pump did you do? What on the hp?
Did you inspect the needle valve seat in the VST? Sometimes a partial blockage can limit fuel filling vst float chamber, could cause motor to run fine at lower rpms, but not at higher rpms (generally this would cause surging?).
Does your motor have a small in-line filter going to hp pump from VST? Could restrict fuel if dirty?
When you replaced flywheel and stator, did you replace with new? Did you test the stator coils? Especially the high speed and low speed charging coils?
Have you tested the TVS? Or, the gear counting coil? These tell the ECM how to time the motor for the rpms it is running.
One last thought, any chance the plug wires are breaking down at higher speeds? Old motors, one or two might?

Again, it sounds like you have done a lot to this motor?
Why put so much time and $ into such an older motor?

Well post back what's going on, or if you find anything, when able. Good luck.

[Ebocaj]

Tested flow and pressure on both hp and lp pumps. All as to workshop manual.
Have had VST apart, cleaned out and needle ect all looks good. Motor def not surging just fully bogs out.

The flywheel and stator are all brand new but I did test anyway and could not find any problem with them.

I have not changed leads yet as the motor doesn't seem to drop just one or two cylinders it is all or nothing, if you get what I mean.

I had an old 1987 blue band merc on the boat and when I saw something newer I thought hey what a good idea!! I was wrong. Have gone a bit to far to give up now.

Will have another look at it during the week.
Any chance faulty temp sensor could cause this problem?

Thanks for the fast reply much appreciated

[seaox230c]

Sadly you did a lot that you might not have to but that's done...you said it boggs out....EXACTLY what rpm does it die..does it vary...this must be done under a load...idle at the dock is no good...If its Exactly 3000 then its a computer controlled shutdown if its not 3000 then its something else and we can work thru it but it takes time and persistence but it will narrow it down eventually...its either fuel or ignition once we rule out one its the other...kind of vauge but it works...the Suzuki manuals are crap...even the factory ones...need your exact motor part number and serial number and we work from there

[Ebocaj]

Motor bogs at about 2850 rpm
I was told that the limp mode will normally limit the motor to 3000rpm but it should also give you a warning ( limit light and oil,temp ect) and it is not doing this.


So name plate has 1998 dt200
Serial no. 20002-751076

Thanks again

[seaox230c]

The computer will limit rpm at EXACTLY 3000 so its not computer driven...does it happen all the time or just sometimes...Easiest way to check ignition is with a timing light... two people help but it can be done with one...you need to pull back the plastic covering on each spark plug wire until you have a clear inch of rubber spark plug lead only...clip on the inductor clamp and run the engine...a good system will light steady and rhythmic...the faster you go the light come quicker but its a steady light...a bad system will start to miss and blink...it is obvious compared to a good one...you need to test every plug when the engine is running bad...more than 1 or 2 will be bad if you can only hit 2800.. You also need to be sure which ones are good or bad..different configurations mean different failures .if they all seem good when the engine is bad then its a fuel problem and we go a different way. If you work alone its difficult to hold the light and drive the boat I spliced in 5 feet of wire into the inductor clamp run so it reaches into the boat better..I put a rubber band on the trigger and put the light on a towel and aimed it at me so I could watch the light when driving it takes time but its better than throwing tons of expensive parts at it good luck

[Solarman]

I'm feeling you should check the throttle valve/position sensor, you have said it runs great till it hits the same rpms, this could indicate the tvs/tps fails at that point in the throttle.

Just my thoughts. Good luck.

[Ebocaj]

Unfortunately the fault happens every time. I will have a go at timing on sat.
Just a question on the 3000rpm computer limp mode, can it cause this problem and not bring up a fault on monitor gauge?

I have a spare tps sensor so I can always give that a go

Thanks for all help will let you know the outcome

[wilbur1]

What about a neutral switch out of adjustment? The engine will think its in neutral an only run 3000rpm without any lights. He is saying 2850 but the tach could be off that much. Just a thought.

[seaox230c]

the tach is usually dead on...I had issues a few years back and did extensive t/s see missing at speed for my saga...whenever I induced a computer limp it went to exactly on the button 3000./..it also gives a light and warning horn so I would assume his problem is something else..there are pulser coils and counting coils and many other electrical things it could be..but each gives a specific failure ...his engine bogs at 2800 is generic and could be the result of many things either electrical or fuel driven ..another simple test is to put a fuel pressure gauge on the fuel rail and read during his engine failures...if the pressure remains stable at 35-40 then there is no issue with his fuel system what so ever and its an electrical problem...with this engine you need to know whats not broken in addition to what is broken and the manuals are almost impossible to decipher...I don't know if the efi's had a neutral switch...my 03 did not

[Ebocaj]

I did have a fault with spark due to neutral switch on the motor but I have bypassed this since the hand piece has one in it. Fuel gauge idea sounds good to so I will take plenty of gear with me to try and track it down in the one day

[Solarman]

Make sure you have the neutral switch correctly bypassed, otherwise it will always limit rpms.

Good luck.

[wilbur1]

Maybe that is the problem? Im betting on something simple.

[Ebocaj]

Don't see how you can incorrectly bypass a simple switch. I am confident it is corrrect.
Had boat out on water with fuel pressure gauge and timing light.
Fuel pressure never dropped under 40psi even when the fault occurred . Checked every cyclinder with light and all seem to be consistent with each other even when the fault occurres. Only difference is the speed of the light slows with the motor when it faults. Again though they are all the same in this condition.

Any ideas?

[redlowrey]

If you are running that engine with the neutral switch on the engine bridged, you will defiantly have a problem, because the switch should be open when it is in gear, closed in neutral open in gear, it is probably the injectors dropping out when it bogs down.