About to make it an anchor

[T.Hair]

1989 dt85 2 stroke not idling in gear. Run down, bought first boat ( without water testing dummie ) she'll start up and purr like a kitten on the ears or in the water, but won't run in gear on the water. Compression is 150-135,150. I've rebuilt ( blown out, replaced gaskets,needle valve and cleaned the inner carb well ) the carbs, replaced fuel with known good gas, did a decarbon on her and am still getting carbon deposits in the plugs but continually clean and check plugs to ensure they're good at test time. I'm getting good spark at all 3 plugs. I'm not sure what I'm overlooking but obviously it's something since she won't stay idling when put in to gear. If I rev her up a few times raising rpm of engine and " bang " her in gear I've gotten her to ride out once or twice and she runs like a scalded dog but don't want to " bang " up lower end. I'm at my wits end and if no good advice will have to try to find a reputable boat mechanic. Thank you in advance for any direction.

[tommybe1]

feel your frustration, im a first time boat owner with a similar problem, sounds like maybe a fuel issue. did you check the tank vent and also the valve off the tank, mine was plugged with goo, put in a straight thru connector. good luck, hope you find the problem, please post back if you do.

[Harper]

Stay with us, T. We have some fairly knowledgeable 2 stroke folks here (I'm not one of them, unfortunately). May take a day or two but you'll get some suggestions. Help is on the way.

[T.Hair]

No, I did not check tank vent due to bypassing gas tank temporarily to ensure proper pick up etc. I'm hoping so re some direction because I'm already researching good mechanics lol. Thanks again folks.

[Solarman]

Thair, in the first place, the plugs do tell a story. Let's understand that rich dark plugs, indicate a rich fuel/oil mixture, and idling on the ears isn't where a boat should be.

The air mixture side of the carb is extremely important, what do you have each of those air mixture screws set at? Do you have a Suzuki manual for your motor?

These 3 carbs you have are extremely easy and good carbs.

Remove only the bowl, float assy, needle valve w/seat, and jets inside bowl. Remove the TPS (throttle position sensor), air-mixture screw, and #4 air pas-sage screw (see below) to soak each carb. All the linkages leave alone.

First on the top of each of your carbs is a screw (#4 on parts listing), at the bottom (end) of the air mixture screw. It is important to remove this screw, and air mixture screw when soaking these carbs for cleaning. These air pas-sages being clean are critical for your motor to idle (if blocked [your problem?] your idle will always be too rich). After a good soaking, these pas-sages need to be blown out with compressed air thoroughly. Once done re-assemble each carb, and set air-mixture screw at what the manual specs call for (all carbs identically), the factory setting/ adjustment on each carb is fine. Do not adjust again, till next cleaning.

The needle valve adjustment is very important too, because it opens and closes the fuel entering the float chamber (if float level is set too low, the motor runs out of fuel at wot; if float level is set too high, fuel overflows the bowl and runs into the carb throat, also flooding/choking that cylinder.) If set right, and there are no problems with fuel restrictions before the needle valve (remember low fuel flow acts like "out of fuel" at higher rpms), the carbs should be good.

If you haven't done everything mentioned above, including blowing out all air & fuel pas-sages with a good compressed air nozzle then you should re-do those steps. Once they are properly cleaned they run beautifully, until old fuel sits up in them for several months again.

If you have changed any idle screw settings, you may have to change that again.

The gear counting coil (top at flywheel), TPS (at carb), pulse coils (under flywheel), magneto, CDI/ computer all control firing the coils & plugs (timing - not adjustable).

Good luck, post back when able to let us know how it's going.

[T.Hair]

Thank you solarman, I did not remove #4 but will redo carbs and undo that screw, clean it etc. I just can't figure out if it's because the compression is on the threshold on that second cylinder or if it is fuel related re carbs. I will keep posting progress / failures to not only figure it out but maybe help someone else with same problem... thanks again.

[T.Hair]

So, I rebuilt the carbs again, decarbed the engine, cleaned plugs again ( was finding chunks of stuff inside#2 cylinder plug but replaced plug which I'm unsure if this is from the decarb on the engine or the indication of a serious cylinder problem) and still nothing. Everything seems well with timing etc, idle air screw mixture @ 1 turn out per book. Looking into rebuilding her but obviously being an 89 question there is, is it worth it to rebuild or just repower?

[Solarman]

thair, ..."finding chunks in plug" (what is it?)..."still nothing" (what kind of discription is this?), i am on the opposite side of a computer screen reading your words, trying to help / identify /correct your problems, and this is the best you can do?
i do not have a crystal ball, to see what you see, or hear what you hear. you are my eyes, ears, and hands.
what you find, hear, and see is important, but it isn't easy to show me in words, but do your best with observing /telling me what's happening, and what you feel it is doing.

with a little help from you, and a little help from us i think you can get it running again.

post back when able, good luck.

[T.Hair]

The chunks appear to be like hardened carbon but it develops between the spark plug diode and inside the spark plug wall. ( also have turned engine over with plug out to see if any sediment etc comes out and nothing ). As for the engine overall, it starts right up ( on ears and in a tub ) once warm she'll rev up great, idle back down fine , go into gear ( obviously not like being in water , I know ), I'll let her run for an hour, revving her up at various times ( always great response with throttle etc. ) put her in the water and she'll start up, idle just fine , go to put her in gear and she simply dies, I can sometimes rev her up and get her to " bang " into gear ie making more noise than it should due to speed of engine when going into gear but obviously this is bad. I've been very meticulous with the carb rebuild and have not been finding anything that is suspect ie dirty fuel, particles etc. When I adjust the idle up to try to compensate/ rule out idle speed it is too high in re to putting it in gear.
Thank you for any direction to look.

[Solarman]

are you premixing oil and gas?

You need the manual to know what wires to check. All must be tested by the Suzuki manual specs.

check the rectifier / regulator for proper voltages in and out.

Test the gear counting coil (location/ distance to flywheel is important, it has to count each tooth and space on flywheel).

Test TPS (throttle position sensor). per book this may require a special jumper wire.

Good luck, post back when able, to let us know how it's going, and what you find out.