1987 Suzuki DT 175 running problems.

jcalexander

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1987 Suzuki DT175 Will not pick up and run

I have a 1987 Suzuki DT175 outboard that ran well for a while but lately the engine will not pick up and run. We have tried everything we know of. When the hot foot is pressed the engine will just act like it has no power and it will not pick up and run. It just kind of bogs down and runs maybe 10 miles at hour at full throttle. Anyone got any ideas?
 

jcalexander

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May 25, 2012
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1987 Suzuki DT 175 won't idle down

I have a 1987 suzuki dt175 oil injection engine that ran fine in the summer but now it will not idle down. We tried to adjust the idle with the switch on the engine but that doesn't seem to effect it. I did some custom carb work to it with bigger pilot jets and main jet in the carbs but it ran fine for several trips and then the last time we tried to use it before it got too cold it just would not idle down. We couldn't even get it to in gear because it was idling too high. What could it be?
 

tommarvin

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Tear the carbs apart, remove every part, use spray cleaner on everything ,and all openings, blow air through everything.

Should you reuse the bigger jets IDK, you could try the bigger jets one more time, if everything looks ok when you tear the carbs apart, Did you adjust the floats?

Free factory service manuals at www boatinfo.no/lib/library.html click your make find motor find carb, have it in front of you when you put the carbs back together.

If the carbs don't work the second time, better get right jets.
 

jcalexander

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The last time I had them apart I soaked them for several hours in carb cleaner and blew every single passage out in them. We ran them several times with those jets and I still have the original jets that came out of it. We haven't run it since that day but were hoping that maybe it was the old weather that did it.
 

tommarvin

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Sir Alexander, no disrespect man, rebuilding carbs is harder than it looks. I see a trend here of I just rebuilt my carb and something's not right with the fuel delivery now.

Did you replace all the gaskets? Last dude didn't, he tore the carbs apart three times before he found the leaking gasket. Did you adjust the floats?

Follow the carb rebuild page step by step. peace.
 

jcalexander

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Well if rebuilding carbs is hard then I'm clearly not hearing from the right person. Carbs are a piece of cake. And yes I took them all apart thoroughly cleaned them, inspected every spec of them and put them back together. The floats are fine, I checked them all. The only thing different from the factory and them now is the main jets and pilot jets are out of a 200. But like I said it ran fine for half a dozen trips and the first cold day we got it started acting up. Personally I don't think it's that carbs. I'm pretty sure is something to do with the idle speed switch on the side it not working properly. I'm gunna switch the pilot jets just to check. I'm not a DIY'r that just slung my carbs off and screwed up. There's something else going on as to why it did it all of the sudden.
 

99yam40

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Only things I can think of to cause a motor to run higher Idle RPM is idle timing advanced to far, throttle plates not closing as far as the should( linkage or control cable binding), or air leak causing a lean mix, but do not see that happening to all cylinders at once.

not everyone that posts on forums knows as much as they think they do, so take what you see on the web with a grain of salt and weed threw what is put out there
 

lakensea

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Only things I can think of to cause a motor to run higher Idle RPM is idle timing advanced to far, throttle plates not closing as far as the should( linkage or control cable binding), or air leak causing a lean mix, but do not see that happening to all cylinders at once.

not everyone that posts on forums knows as much as they think they do, so take what you see on the web with a grain of salt and weed threw what is put out there

You are absolutely correct, and the timing is electronically set on that engine. That's also how the idle speed knob works, and there is a throttle valve switch that affects the timing. Check all the linkages for binding and synchronization. Hopefully you replaced all the gaskets. My suggestion would be to visit your local Suzuki dealer and PURCHASE a FACTORY manual so you can properly diagnose your problem.

And 99Yam40 your last statement is oh so true - it's amazing how the internet makes people think they're smart.
 

tommarvin

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Free factory service manuals at www boatinfo.no/lib/library.html Click your make, find your motor, find your page
 

99yam40

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Free factory service manuals at www boatinfo.no/lib/library.html Click your make, find your motor, find your page

I am begining to think you are promoting another web site on here the way you are keeping with that same posting over and over
that is not the correct thing to be doing on a forum sponcered by a web site that sells parts and even the manuals.
I know you are young but if you keep it up there is a chance you will be banned.
You can send Privet messages that will not affect you or anyone else
 

tommarvin

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I'm just trying to do everything I can to help somebody, I have learned a lot here.
How do I send a private message?
 

99yam40

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Click on the name of the person you want to send it to and then click on the private message button .
this site is running very slow for me today. takes a long time to bring things up
 

grid

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Oct 29, 2002
Messages
232
Try something simple, first. The electronic ignition on that engine is heat-sensitive at first start, and time sensitive subsequently. I saw no mention of balancing the linkage for thew carbs. Remove the connecting rod that joins the 3 carbs. The throttle plate attachment has 2 Phillips screws, andf both should be loose to balance the linkage. Loosen both screws, make sure the throttle plate snaps shut. Do this for each carb. Back the idle screw on #2 carb all the way out until it no longer holds the plate open. Leave the linkage off and start the engine (you'll need back pressure like it's in the water). If the idle performs properly, the carbs were just out of synch. With the 2 screws per carb loose, reattach the connecting rod .Open the carbs using hands on the rod and let it snap shut. Hold the rod and tighten all the screws. Run the idle adjustment screw in until it just touches the throttle plate adjustment. Re-start the engine. If it idles too low, you've done the job right, and you can run the idle adjustment screw back in a tad until the engine idles around 750RPM in neutral. Use the electronic switch for fine adjustment.. Hope this works~
 

jcalexander

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May 25, 2012
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We found what was wrong with it. The electronic choke on the control box at the drivers seat had worn out and the contacts had gone bad making the choke stay open all the time and not allow it to idle down. We had to take the control box apart and replace the key cylinder(Which houses the electronic choke) and the kill switch it was hooked
 

jcalexander

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About 3 weeks ago we took the boat to the lake and were playing around with some prop set ups. Well they didn't work like expected so we changed back to our original stainless prop. On that trip out we hit something hard enough in the water to feel it and it bent the prop blade(which i later straightened out) but the engine ran fine that same day with no problems. Then a week later we get it to the lake and it will not stay running. It will crank and run if you push the throttle a little bit but if you release the throttle back to idle the engine will die. It does this for about 30 minutes and then it will stay running. But for those first few minutes it will not idle. Secondly it has started making this blooping noise. And if you actually say out loud "bloop" that is what it literally sounds like. It does this all the time now. Any ideas? Thirdly the compression on all 6 cylinders is 75 psi. The tech said he likes to see 115 psi. Will it do any harm to keep running it like is? Any real ideas of what could be going on?
 

99yam40

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sounds like a lean sneeze
not good to keep running a motor that is sick
 

99yam40

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broke choke switch will not energize the choke, but has nothing to do with the idling too high
 

jcalexander

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I put the bore scope in all the cylinders and all the pistons and cylinders look fine. Not really any symptoms of it being lean though.
 

99yam40

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lean sneeze is a symptom

And find a different compression gauge to see what it says
 

jcalexander

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May 25, 2012
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Thats what fixed the idle problem. My dad grabbed the key and he could wiggle where the choke pushes into the cylinder. The key and choke are one unit in those. Replacing the key and choke fixed the idle problem. The choke switch was basically worn out and was holding the choke wide open all the time.
 
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