1994 DT150 question....HELP

[Needmoremoney]

As a lifelong evinrude person, i just picked up a cc with a '94 dt150 & with no suzuki experience, have a couple questions-
*the horn sounds when turning on the key so i'm assuming it works....now my questions revolve around....no overheat horn sounding so do i have a problem:
*I see what appears to be steam coming from the exhaust up top (under cowel), at least pretty sure it's steam
**the water coming from telltale is cool if i hold the ears tightly at water intake BUT gets hot & pressure lessens if i DONT hold ears tight (they are new & appear to make good contact)
***other then the above & a 'pop' possibly from a fouled plug, it sounds just like the others i've listened to on youtube, & letting it run no more then 3 minutes or so, it sounds the same, start to finish

So, anything i should be looking for at this point?

[Solarman]

If you have good water pressure at the ears then the tell tale should be strong. Also tell tale should not get too hot for your hand. Steam at exhaust is not good, stream indicates something is getting too hot. If cylinders are too hot to put hand on, then thermostat may not be opening up completely? Or it may be time to change water pump?
You should have a monitor Guage with several lights (usually flashes a two digit code when key is turned on, if any recent problems occur in the diognostics system).
If the muffs are snug and pressure good, you might have a sub-water tube, or grommet leaking too much water from the water pump cavity that feeds the impeller, or allows exhaust to impede water filling cavity?
If you put the boat in the water, does the tell tale remain weak or strong?

A good suzuki service manual is good to have if having problems. Today's dealership mechanics don't want to work on the old 2 stroke motors these days. They go for the 4 strokes where the money is bigger.

Post back what you find when able. Good luck.

[Needmoremoney]

So i'm thinking maybe some dirt in the cooling system? I found a barrel & have ditched the ears. Each time i empty the barrel, i find a small amount of sand...getting less each time. Could just be loosening from cracks & crevices in the lower unit, but we'll see. Telltale is cooler then 1st time i ran engine, generally barely able to call it warm, so i guess thats good. And yes, the stream is now strong. An inexpensive infrared heat gun shows mid 120's directed at bottom of t-stats. Cylinders i'd say are hot, but not to the point that you can't hold your hand there. Replacement stats have been ordered. & the steam from the exhaust-its still there, but less then before. I did see a 200 suzuki 2 stroke heading out to the bay this afternoon, at idle speed, there was plenty of steam coming from the exhaust...

The monitor guage only shows 2 lights on-guessing that means oil reservoir is sufficiently filled?

I've also ordered the water pump kit & some grommets.

So i'm HOPING that resolves my water flow issues. Next up is actually starting the darned thing-

Batteries are 6 yrs old, 1 was dry in 4 cells. Saturday i'm gonna pick up a new pair.

So while starting with the charger on, i'm thinking i have a fuel flow problem-pump ball til firm, variously pressing & holding key from 1 to 5 seconds produces mixed results trying to start. Sometimes it starts, sometimes it doesn't & sometimes it runs for 5 or 6 seconds, stalls-like it ran out of gas-then gives me fits trying to restart it (partly due to batteries dying, when i replace them, then i'll be able to crank 'em some more i hope).

I'm not sure i get the 'throttle valve switch' thingie, or solenoid release valve or WHATEVER is supposedly happening when i push the key switch in. Maybe the fuel pump diaphrams are bad? But would they pump ANY fuel? I mean, the engine runs, the trick is getting it to start, then keeping it running. Sometimes it restarts easily, sometimes not.
No rebuild kit available so i've ordered:needle valve assemblies, valve seat & float bowl gaskets & jet holder O-rings, as well as fuel pump diaphrams, O-rings & gaskets. Anything else you think i may need? Throttle valve switch....IS that whats attached to key switch?

I am running off an auxiliary 6 gal tank with fresh 93 octane BP detergent gasoline (from the street) with a few ounces of octane boost, so no issues there.

Below are 3 vids, in order, of how it's running, after just flushing thru 55gal drum, & multiple sprayinga of power-tune. Nothing has been done til i receive the 'tuneup' stuff in the mail.

https://youtu.be/y917oIiAX9s
https://youtu.be/1xXvqjqXL5U
https://youtu.be/EbsnyAwEmnA

[Solarman]

Is this the carburetor version dt150, or the EFI version?
The EFI version doesn't have a choke solenoid, does NOT do anything when pressing the key switch in while starting.
The carburetor version does have a choke solenoid that closes the butterfly plates to reduce air and increase fuel, if the solenoid is working.

How long has this motor been sitting up?

Good luck, post back when able.

[Needmoremoney]

Carbs, 3 mikuni's. I hear Something click near the carbs when i push in the key switch. Not sure if butterflies are closing, or already closed. Gonna hafta look closer when i'm off on Saturday.
I know the last owner, he does NO WORK on his own boats, this was just to get him back & forth to his big boat on fire island, so not at mercy of ferries. He used it probably 2 dozen times each of the last 2 seasons, mostly for 20 minute trips each way. What he told me about starting this thing made me assume batteries were on their last legs, so yes, new ones on saturday. As for starting it....he kept multiple cans of starting fluid on hand

[Solarman]

The starting fluid is not good for 2 strokes, they rely on oil mixed with fuel to protect bearings, etc.
If you have a barrel to run motor, add some corrosion flush or vinegar (5, or 6 gals vinegar - less costly) to the barrel. Run motor for couple hours in stages (allowing solution to cool when it gets too warm). Use the temp gun to see if areas around cylinders are cooling down better as you flush.

If fuel problems still exist, you may need to clean carbs thoroughly, blowing out all air & fuel pas-sages with compressed air, then setting carbs back to factory specs. Do not mix-up parts between carbs, and record air-mixture settings to compare with manual.

Needing starting fluid is a direct indication that air-fuel mixture pas-sages, jets are restricted, or not adjusted properly.


Good luck. Post back what you find when able.

[Needmoremoney]

https://youtu.be/X4CAcPjDXZQ

https://youtu.be/y917oIiAX9s

https://youtu.be/Oga0O_MIgoM

Ok, 1st vid is when i 1st got it started...it ran...was best i could say. Pretty rough, lots of popping, VERY hard to start, even warm.
2nd vid was in a bucket as opposed to ears, still trying to figure what the bugs were.
3rd vid is where i am today-2 new batteries, new plugs, new impeller & gear oil, 3 rebuilt carbs...now both fuel pumps were pretty bad. Rebuild kit is diaphragms & o-ring. What it doesnt supply is the plastic valves inside the pumps. They were gone. Had to scavenge from a mercruiser kit...which by the way includes the valves. They're a hair smaller but seem to work. So, all that and-NOTHING. Still a boar to start. Hmmmmm. So we took apart the 'starting valve' or whatever its called. NO fuel was flowing thru it. We had to drill out the hole where the needle valve is and....FUEL FLOW. AND....IT STARTS RIGHT UP! The carbs were adjusted-they were way out of sync, all 3 had butterflies in different position! Replaced the water pressure guage & added temp guages on each head. Water pressure is 12-15psi cruising, about 5psi at 1k rpm's, 2 psi at idle/600rpm. The temp guages show head temps right under 140 degrees around 1000 rpm's, they go just over 140 at idle & cruising, they drop a bit under 140.
At that point, i was satisfied. We cruised about 3/8 mile up boat ramps river, at 1k rpm event-free. Coming out of the river, i opened it up, 4-4500 rpms, up on plane, for several minutes til i got to next river. A mile up that river at 1k, was again event-free. As far up the river as u can go, i attempted to turn around-needing to reverse/forward a couple times & it stalled a couple times. No big deal, it started right up. However, final time it restarted, i could not 'find' neutral. As soon as i moved the lever, it was in gear. I could not get it to go into neutral. Heading back out the river, behind a much larger boat, i kept having to throttle down & put it in reverse to avoid getting to close. Eventually neutral 'returned' & the remainder of the trip out of the river was fine. Entering the bay, i stayed close to the rivers for 10 minutes or so, at cruising speed, 4000+ rpm with no issues so i decided to take the 4 mile ride across to fire island. Got there, no issues, into the marina-full, so again the forward/reverse maneuver to get out caused a couple stalls & the no-neutral issue to resurface. Left marina, thru channel at 1000 rpms, got out of the no wake zone & opened it up...only to stall. The primer bulb was empty. Pumped it up, it started, ran, stalled & was empty again. After several attempts & the thought...i knew i shoulda re-upped my seatow plan on THIS boat....it took off & was fine. 3/4 of the way across, my rpms dropped to 3000 & boat came off plane. A bit too choppy to mess around in open water, i restarted several times & did the last mile at 2500 rpms or less trying to keep the nose down. Just before the marina, it opened back up & i cruised to entrance just fine. As i throttled down, it stalled in the entrance. Several times.

So, it always restarted, it idled just fine. It was too choppy to check primer bulb every time, but it did not seem full/hard during most of the 'events' i was able to check. The 'no neutral' issue....cable adjustment or lower unit shifter issue-which would you think? As for rpms dropping to 3000 & losing plane...the suzuki monitor shows oil (tank is more then half full), monitor shows no temp issue corresponding with my auxilliary temp guages & i did not rev over 4500, so i'm not sure if its a malfunction in the suzuki monitor system, an actual problem or some other gremlin.

Tomorrow i am going to replace the crapola west marine bulb & hoses (my other boat suffered delamination of the inside of the bulb & hoses TWICE, most likely due to alcohol that our govt says our fuel needs. So i've learned that lesson.) I am also going to try to use the little red auxilliary fuel tank instead of the inboard tank. You think i'm on the right track with the bulb and/or fuel tank?

Other then that, it actually seems to run rather well. Any suggestions as to where i should be looking to clear up todays (hopefully minor) issues?

[Solarman]

OK first you mentioned carbs?

"Carbs, 3 mikuni's. I hear Something click near the carbs when i push in the key switch. Not sure if butterflies are closing, or already closed. Gonna hafta look closer when i'm off on Saturday. "

If this is a dt140, it has 4 carbs, not 3.
The clicking you hear should be a choke solenoid mounted on the top carb, attached by a linkage to each butterfly at the front of each of the 4 carbs. When you press the key in, each of those butterfly plates should close, choking all 4 carbs of air, this increases fuel (less air).
If this is a dt140, it should also have a throttle position sensor (TPS) mounted on the bottom carb. This sensor tells the electronic control module (ECM) where the throttle is with respect to rpms to adjust timing. The timing is also affected by the gear counting coil that counts each tooth of the flywheel (at back of flywheel). This gear counting coil has to be mounted a specific distance to flywheel to count each tooth. If too far away it will miss counting the teeth properly (or if bad), and timing will be off.
If the TPS is bad, then you will have dead spots when pushing throttle forward. Or, it may stop advancing timing, and limit performance?
You mention the bulb was flat/collapsed. This usually means something is blocking flow before the bulb, either the vent is blocked, or the fuel flow is blocked (possibly a check valve/flow valve at the outlet of the tank?).

I can not tell you much more than this till I know what you actually have?

Post back when able.

[Needmoremoney]

It's a dt150, with 3 mikuni's & that 'starter valve' thing that mounts to the side, above the carbs, & dumps fuel in when actuated during cold starting. It does NOT choke the carbs, or in any way physically do anything to the carbs-its just an added dumping of fuel.
No, the primer bulb didnt flatten as if a blockage in the fuel line. It just emptied of fuel (as if an air LEAK), & caused the engine to stall. Several pumps & it fired back up. I picked up a real, quality-built omc primer bulb & some real marine fuel line-not the plastic west marine junk. I'm off on saturday, so tomorrow i'm going to attach it to a 6 gal auxiliary tank & see how that works.
So in retrospect, my issue right now is revs cutting back to 3000 while cruising at 4500-4800. The suzuki monitor/safety system does that when over-revved, over heated, or low oil level. My 2 temp guages on the heads were well under 140 degrees, i have half a tank of oil (another 2 qts i'll add tomorrow), & i was well within rpm range.
If the TPS was bad, it wouldnt be intermittant, would it? The engine ran fine for 45 minutes, then began cutting back revs to 3000, thus coming down off plane. Is there something in the suzuki warning system that could provide false info, triggering the 3000 rpm max to kick in, causing a correct running engine to limit revs? Could an air leak in the fuel system cause the engine to drop down to 3000 rpms max? When the engine was in that 'rev limited' state, it still revved over 4000 in neutral-just not in forward gear.
So tomorrow morning i'll be trying the new primer bulb, hose & portable tank. Any other suggestions where to look, if that doesnt cure the 3000 rpm limit issue?

[Solarman]

That's my mistake, you did say dt150, and yes it has the 3, 2 barrel carbs, 1 barrel for each cylinder.
Yes, yours will most likely have the primer style choke as-sembly. The primer activates (when pushing key in) the diaphragm to push fuel into each barrel on the carbs it is attached to (it may only feed one, two, or all 3 carbs).

The TPS can act up intermittently, but the manual should tell you how to test that sensor. If it tests good by the manual, then it's probably good. If it skips readings, goes blank at certain areas, then it is probably bad. It should give smooth readings from idle to WOT.

Another common problem is the gear counting coil, it has to read each tooth of the flywheel, this is why the distance to the flywheel is important.

On all 3 carbs, the low speed mixture screws should be set by the manual (same setting for each carb).

Using a spare tank is a good step to see if tank is causing problems. But you should use seafoam, or a good fuel additive in every tank of fuel.

Good luck, post back when able.

[seaox230c]

Hi I know how the newer f/I models work not exactly sure about the older carbs but prob similar. The 3000rpm limit is limp mode caused by low oil flow..low oil qty... overtemp... or over rpm. Each one of these failures should illuminate a corresponding light and buzzer when it goes into protect mode. Is the rpm 3000 exactly or does it vary by a few hundred if it varies it is not a computer driven protect ...easiest way to rule out the overtemp is to take both of them out of the block and just hang them inside the cowl. Your check engine light should be flashing a code when it goes off but usually no buzzer or protect mode. flash__flash flash flash then a wait then repeat something like that...on steady is a fuel injection computer failure

[Needmoremoney]

Ok. So its been running pretty good on the open seas....well the great south bay at least. An occasional stall when throttling down, but it starts right back up & continues on its way.
That is until now. Pulled into a fire island marina, it stalled, restarts as usual, but now, it stalls every time increasing throttle IN GEAR. It goes into gear, and idles, but increase throttle & it stalls. For now, its sea tow. But any ideas what i'm looking for now?