Suzuki DT 150 hp (Super Six)

[Jokerit]

Greetings from Finland,

I have Suzuki DT 150 hp (V6) and so far it has worked fine.
If I remember right it is from year 2011 but has been used
only around 65 hours. Inside it seems like a new.

It has worked well but last summer it however started to behave
so that for some reason for example when driving with 3000 rpm
it "stopped" frequently for 5/100 seconds and then continued again.
You could feel speed decrease a bit and also sound.

On high end it previously took max 5500 rpm but now only 4900 rpm.

I have cleaned the bottom of the boat and it is clean. I have also
changed the plugs two times and that did not remove the problem
as described above.

Any idea what should I try next?

(motor has been installed on 6 meters long day cruiser, Yamarin 600 BR).

I hope you see my mail and suggest something.

Thanks a lot in advance,

Brgs,

Jokerit

[D'oh999]

My old 130 HP Yamaha, took out the Upper Lower Unit Bearing a few years ago. It started on the way to the Cabin, a couple of RPM drops, motor sounding laboured. On the way back, it happened twice, then locked up from 4000 RPM.

[Jokerit]

Hi Dóh999,

Thanks for your reply.

So, what do you think might be wrong in my Suzuki?
I have checked plugs, I have checked bottom of the boat and they are ok...

Motor starts up normally and works other ok but sometimes makes things I described on my first mail.

[Solarman]

Greetings from Finland,

I have Suzuki DT 150 hp (V6) and so far it has worked fine.
If I remember right it is from year 2011 but has been used
only around 65 hours. Inside it seems like a new.

It has worked well but last summer it however started to behave
so that for some reason for example when driving with 3000 rpm
it "stopped" frequently for 5/100 seconds and then continued again.
You could feel speed decrease a bit and also sound.

On high end it previously took max 5500 rpm but now only 4900 rpm.

I hope you see my mail and suggest something.

Thanks a lot in advance,

Brgs,

Jokerit

Jokerit, it is difficult to understand what you are saying in your message above.
Is your motor skipping/miss-firing/ or just shut off when running at 3000 rpms? Stopping for 5/100 seconds, then going again? Is the motor shutting off? Or just dying down to idle, then starting back up?

Please explain a little better if possible. I understand you are in Finland, and not good with English.

In Finland did you buy motor new/used in 2011? Is this motor EFI, or does it have carburators for gas? I did not know they still made DT150's after year 2000?

Do you have the Suzuki service manual for your motor?
For 2011 motor to have only 65 hours in 2018 is unbelievable.

Post back when able. Will help if i can understand what is happening.

[Jokerit]

Hello!
Ok, I try to be more precise.
Well, when driving at 3000 rpm motor does not suddenly shut down (speed to zero)... no. But for 0,05 second motor will go unsteadily and rpm´s decrease a bit. Then everything goes again normally for few seconds and then again for 0,05 seconds rpm´s will decrease but motor does not shut down totally. You can feel boat speed to decrease a bit and also you can hear that motor goes unsteadily.

So some type of miss-firing might take place, my guess?

I am not a superb with motors but I think it is EFI.
I do not have manual for the motor.
I am the second owner of the motor and somebody sold it for me because he had only 2-3 hours per summer time to drive with the motor.
Motor is clean, almost unused and no any oil leaks or dirty when opening the cover.

Thanks for your activity... let´s get this solved!

[Solarman]

Ok, take a pic of serial number plate and add it here. It should be on left, or right side of motor on bracket that attaches to transom. This should tell me what year motor it is.

It would be better if you have suzuki service manual for the motor. It has testing procedures for different sensors and electrical components that might be getting old.

It sounds like one of the cylinders is miss-firing, or maybe arcing (sparking) to ground while running. It could also be one of the ignition timing coils/ sensors could be going bad. But i can not tell what parts your motor has until i can look up parts on it.

when you reply back again, you should be able to add the pic of the serial number plate there.

Post back when you can.

[Jokerit]

Ok, I will post that later today or during weekend when I go for a weekend... thanks in advance!

[Hoosmatroos]

I think it's a DF150 instead of a DT150

[Solarman]

Why say that Hoos? One reason i asked for the id plate, to know what year and model it is. New to him, doesn't mean new motor. But i am questioning the year still.

[Jokerit]

7B26EDA0-582C-4E8D-B867-1DD280523928.jpeg Ok

[Jokerit]

E8150FDB-2F14-4CCF-B1E4-F113A3FBDA74.jpeg Ok

[Jokerit]

Can you track motor with that plate above?

[Jokerit]

Could this be something to do with fuel filter?
If fuel filter is old, how do you notice that in daily cruising? Any influence on top rpm?

[Solarman]

It appears to be a DT150 made in 2000 (15003-0312... that year only).
Parts listings do not show carbs, only EFI model.
I will search parts listings, for possible causes. It still would help you to buy the suzuki service manual if you plan to keep this motor, it will be very useful in testing different electronics for problems.
will post back later with what i find.

[Solarman]

Joker, you need the Suz service manual. The manual will tell you how to test the electrical items with an ohm meter, and what readings are good and bad.

I am as-suming you have looked at wire connections on motor and at dash controls for loose, corroded connections. Loose wires can bounce with small waves and cause mis-fires if related to ignition switch or kill-switch.

You should test each coil for leakage, on both sides, then test sensors, and neutral switch.

You are our hands, eyes, and ears in this search for this problem. Please understand that everything has to be relayed back here in great detail to help you solve it. If you can not help us to help you, then you will have to take it to a qualified suzuki technician.

Post back when able, good luck.