1985 Suzuki DT65

[pejay288]

I have a 1985 suzuki dt65 3 cylinder 2 cycle outboard, it works fine out of the water on my driveway, and works fairly ok on the water too. I have never had this problem before with it, untill recently.. and i haven't done anything different than usuall.<br /><br />Ok the problem is that the engine runs fine in gear at a very slow speed, but when you start to increase the speed quickly the engine just cuts out and stops, but if you increase the speed extremly slowly and then leave it just at a very low rpm before it cuts out, then wait a few seconds you can hear the engine make a higher frequency noise and then the rpm starts to go up, and then it works completly fine at any speed, untill again you turn the engine off, and you have to go throught that all over again..<br />Does anyone have any ideas on why it is doing this?<br />Thanks. Peter.

 

[bossee]

Re: 1985 Suzuki DT65

Hi,<br />One thing I would have a look at is the fuel pump diaphragm.

 

[jim dozier]

Re: 1985 Suzuki DT65

It sounds to me like you are running lean on the idle take off and/or the high speed jet. The high speed or main jet controls the mixture at high speed and also provides fuel to the idle circuit which I believe is then modified by the idle air circuit (which has the air adjustment screw). If the main jet is clogged or dirty, you will be lean at both high speeds and idle neither of which is good for the engine. <br /><br />Alternately, it is possible that the idle air adjustment screw needs adjusting to a richer setting (screw in=less air). Either way it sounds like its time to remove the carbs and do a complete cleaning/rebuild.<br /><br />Since its a simple thing to do, I would replace the fuel pump diaphragm like Bo says while you're at it.

 

[pejay288]

Re: 1985 Suzuki DT65

Thanks for that guys, I will try and adjust the Lean/Rich adjustment screw, but are you ment to adjust it while the engine is in use on the water, or while it is ticking over? Sorry im a bit new to this part of engine repairs! But it's good im learning lots.<br />Thanks again. Peter.

 

[jim dozier]

Re: 1985 Suzuki DT65

There is a factory range of number of turns out from lightly seated for the idle air screw. The final adjustment once its within the factory range would be done running at idle rpm, in the water (not the driveway), and in gear. These screws meter air, so screwing in in makes it more rich. I would shoot for the optimun smooth idle then screw it in 1/8 turn. This will make start ups easier and a smoother take off. This is where a manual really comes in handy. No one should be without one.

 

[rdxgator]

Re: 1985 Suzuki DT65

Peter,<br /><br />I experienced a similar problem yesterday. I also notice that the engine seems to be idling high when i run it on the trailer.<br /><br />Have you discovered what the problem was yet? I was reading my manual and it sounds like it may be the CDI unit. My DT65 is a 1994.

 

[jim dozier]

Re: 1985 Suzuki DT65

Rdxgator, don't evaluate engine idle on the trailer. You need backpressure on the engine. Put it in the water, if it idles fine you're OK.

 

[rdxgator]

Re: 1985 Suzuki DT65

understood.. but i'm comparing it relative to how it idled on the trailer before I was having the problem.<br /><br />My problem is that the engine dies when i try to throttle up. I took it out yesterday (i haven't run it in 3 weeks or so). I have a long no wake zone to idle through so the engine was warm. I got it up on plane for about 3 or 4 minutes and then had the problem. started back up but couldn't throttle up at all. had to idle home.<br /><br />I'm wondering if the high (very high) idle problem on the trailer is related. Because it didn't use to idle that high at all.