DT150 won't go over 2000 rpm's... help please!!

[Solarman]

Generally the sensors are more temp related since around the latter '80s? More so than flow related. The initial signals/beeping may be related to sequential starting-up procedures. The timing of audible beeps turning off when tell-tale flows, I believe is coincidence of timing, how long it takes to initialize sensors/other readings?
Sorry, the monitor guage is what's connected through the system, but more so as indicator lights just for information as to what's going on. The tach just reads the rpms. However if something is not reading good, that may throw the motor into a fail-safe condition limiting rpms to ~2k rpms until the problem is corrected, and that reading is normal.

Many boats do use 4- blade props (if properly set-up), but generally for getting quicker "hole-shots" to get going. As I said, 2 blade props were for top-end speeds (racing), 4-blades for loads, quick take-offs, and 3-blades to give the best low and top-end response.

Good luck, let us know how it goes.

[Importkillerrr]

Generally the sensors are more temp related since around the latter '80s? More so than flow related. The initial signals/beeping may be related to sequential starting-up procedures. The timing of audible beeps turning off when tell-tale flows, I believe is coincidence of timing, how long it takes to initialize sensors/other readings?
Sorry, the monitor guage is what's connected through the system, but more so as indicator lights just for information as to what's going on. The tach just reads the rpms. However if something is not reading good, that may throw the motor into a fail-safe condition limiting rpms to ~2k rpms until the problem is corrected, and that reading is normal.

Many boats do use 4- blade props (if properly set-up), but generally for getting quicker "hole-shots" to get going. As I said, 2 blade props were for top-end speeds (racing), 4-blades for loads, quick take-offs, and 3-blades to give the best low and top-end response.

Good luck, let us know how it goes.

Tomorrow my son and I will be going back up to lake hopatcong to try it out. If you listen closely around 7am est you may just hear me yelling hopefully it was just an overpropped issue and everything will be a-ok... Lol.

If I get out there and still have issues is there's anything I should check BEFORE taking the boat back off the water? Remember, it's over an hour drive one way for me to get back to water to test anything. If you're curious about this reading while doing that and it needs to be in water to test, please let me know now. I'll bring my multimeter and a basic tool kit with me just in case.

Solar and Murray...Thank you for your help this far!!

[Importkillerrr]

Also, I had a question.... Back in the day when I was running a performance Bass boat I used low water nose cones and hydraulic jack plates and we all ran custom made aluminum hydrofoils from a guy named Brian down in Louisiana, they were called Brian foils,I think he still sells them online.

I had a foil laying around my shop so I threw it on the Suzuki. It fit perfectly and seemed to do is job but I've never ran one on a heavy bass boat with a normal 150hp engine. I'm thinking I should wait until I get it to run like it should before I start adding stuff to it but Im also running a lot more weight than it did in 1991. A starting battery and 3 deep cycle batteries for a36v trolling motor adds weight quickly. With that added weight a hydrofoil might be needed to keep the back deck carpet dry when coming down off plane.

Do you guys think I should run the foil or take it off?

[Importkillerrr]

I didn't get to go to the lake Friday, life got on the way.
I was able to run the engine on muffs in the driveway though. I could NEVER get the motor to run on muffs before, just wouldn't get any water pressure so I bought a trough to use as a test tank. I read a thread about blocking off the other water intake ports on the lower unit with duct tape to build up the water pressure and holy shit!!! It worked!!
I ran it on muffs and it easily went up in rpm range,4k....5k... Even hit rev limiter easily. No load of course but I feel much better about things

[artdf175]

are you using an engine interface cable to see okay to see info on your a MFD.

[Moonlighter]

Don’t forget guys, this is an old DT…. A 2 stroke. No fancy interface cables and digital gauges LOL!

[Importkillerrr]

Ok... We took the boat out yesterday. That hour and a half drive to the lake sure was an anxious one!! Starting cold (44 degrees yesterday morning) was better than it ever started before. Once we primed the bulb it started and idled like a dream. Idled through the no wake zone without a hiccup.

Got to the no wake bouys and rolled into the throttle and it jumped right out of the hole onto the pad and it ran better than I could of imagined. Then it didn't.

After running wot for a hundred yards or so it fell on its face back down to 3000 rpm. Trimming wouldn't help anything, the motor wasn't bogging or missing it felt like it was being held back it then shut off like I turned the key. It would restart but wouldn't go over 3k.

I then remembered that a few years ago when I restored the boat I replaced the safety clip thing that you clip to your life jacket. Not just the clip, I wired in a complete new one into the control box because the old one was missing. I pulled the clip to turn off the engine to confirm it was working. I grabbed the button with plyers and worked it fully in and out a few times because it looked like it wasn't allowing the clip to fully seat. Small pieces of plastic fell out allowing the clip to fully be inserted now.

My son went to the back deck and said the fuel bulb was soft and empty so he squeezed it until he felt fuel flowing through it when he squeezed. Motor started and I never had another issue all day. It ran at around 40mph@ 4600rpm all day long. It was a dream day after the rough beginning.

Thank you to all for the help!!

[Importkillerrr]

Why me?!?!? I seriously think I peed in god's Cheerios at some point. We took the boat back out today after raising the motor 2". last time out the motor ran like a dream after a rough start. Today it was a completely different outboard. It just wouldn't run

The only thing I did from last week to today was to raise the motor and I installed a new fuel gauge sending unit. I put a can of berrymans into the tank along with 30 gallons of fresh fuel and went to the lake. That's it.

The engine just wouldn't run over 2000 rpm's unless I pushed in the key to choke it much like it started out last time but last time once the motor got warm I never needed to choke it again...
This time... Holding the key in would kick the motor like it had a turbo and occasionally at the beginning of the day, once it started to get going I could let off the key and it would continue to run at WOT and I was cruising at 4500-5500 rpm and between 35-45mph. Until I got off the throttle, then I would need to push the key again to get it going again. As the day got longer those moments were few and far between to the point where at the end of the day it wouldn't even idle without pushing the key in.

Did I blow a fuel pump? Also noticed that earlier in the day, when I pushed the key in to get it going and the motor ran the next 10+ miles at wot without any help from the key that my mileage was amazing! I drove roughly 20 miles and used 1/4 tank. The last 7 miles I drove needing to hold the key in to make the motor do anything. In those 7 miles I used almost 3/4 of a tank!!! It's definitely fuel related, it seemed liike a diesel losing prime... Does this sound like a fuel pump?

[Solarman]

Actually, it sounds more like the carbs and fuel passages need to be cleaned properly by soaking well and blowing all the jets and passages out thoroughly!

But you had said they (carbs) were cleaned out? Have you inspected the low pressure fuel pumps for damaged check-valves?

At this point it sounds fuel related too.

Good luck. Let us know what you find out?

[Importkillerrr]

Actually, it sounds more like the carbs and fuel passages need to be cleaned properly by soaking well and blowing all the jets and passages out thoroughly!

But you had said they (carbs) were cleaned out? Have you inspected the low pressure fuel pumps for damaged check-valves?

At this point it sounds fuel related too.

Good luck. Let us know what you find out?

I never cleaned out the carbs, I drained the bowls but that's about it. Only thing I ever touched on the fuel side was I replaced the filter that's attached to the side of the block. I'm not good with carbs, never have been but I'll give it a shot, at this point I have all winter as they lowered the lake so much for homeowner dock repair that I now can't get the boat into the water until they raise it back up in March.

I ordered the manual yesterday so I'll hopefully be able to follow it so I don't screw up the carbs.

Thank you for the continued help, it's very much appreciated!

[Solarman]

Take pics of each side of each carb and pics of all carbs together both sides. These will help you get all hoses and connections/everything back together like it was.

I believe you have 2 carbs with joined castings for top, two cylinders.Then the same 2 carb set-up for the middle cylinders, and another 2 carb casting for the bottom two cylinders. Each of these castings are two carbs, with 2 float bowls and 2 sets of jets. Only one of the 2 carbs will soak in a gallon can of carb cleaner, then you will need to flip it over to soak the other carb. Only remove the float bowl and that carb's jets to soak.
Before removing each jet, record the number of turns inwards (until lightly seated) for each one, on each carb. Do not mix parts between carbs. Soak each carb and it's jets separately (do only one carb at a time). After soaking each carb, blow out every little hole in the carb body, and jets.

Post back if questions.

[Importkillerrr]

Take pics of each side of each carb and pics of all carbs together both sides. These will help you get all hoses and connections/everything back together like it was.

I believe you have 2 carbs with joined castings for top, two cylinders.Then the same 2 carb set-up for the middle cylinders, and another 2 carb casting for the bottom two cylinders. Each of these castings are two carbs, with 2 float bowls and 2 sets of jets. Only one of the 2 carbs will soak in a gallon can of carb cleaner, then you will need to flip it over to soak the other carb. Only remove the float bowl and that carb's jets to soak.
Before removing each jet, record the number of turns inwards (until lightly seated) for each one, on each carb. Do not mix parts between carbs. Soak each carb and it's jets separately (do only one carb at a time). After soaking each carb, blow out every little hole in the carb body, and jets.

Post back if questions.

IMG_2800.png

Just so that we are on the same page, this is a diagram of my carbs and all the fun that awaits lol

[Solarman]

Not a clear pic, but yes.
Each carb is like a 2 barrel carb, but each one is set-up for 2 cylinders. An each barrel/throat has its own jets. But each 2 barrel carb has one float bowl assy for both cylinders. Each carb has 2 sets of fuel and air passages, so soaking and blowing each passage way, and all the jets (6 sets) is very important.

Remove one 2 barrel carb assy at a time, remove the float bowl, float & needle jet assy, the jets for air and fuel passages (electric choke assy and TPS if on that carb). Then submerge entire rest of carb and jets in carb solution (read directions on carb cleaner). If entire carb won't fit in container soak one end then flip for the other half, or get a larger container? Once entire carb is cleaned then blow-out every hole/passage in carb and jets until clear and dry (do NOT use wires to clean holes - air pressure ONLY). After completed you can reassemble each carb. Reset each carb float setting per manual, and re-set each air mixture screw for each barrel per manual (all the same setting), then wrap a clean cloth around carb and remove the next carb for the same cleaning.

Once all 3 carbs are cleaned and finished, re-install bottom carb, then middle carbn, then top carb. Then everything else to finish.

Good luck, post back on how it went.