Suzuki DT 150 Smokin'

[UB72]

I purchased an Alumacraft a few years ago that came with a 2003 Suzuki DT 150 with oil injection that has run super each and every time out on the water until yesterday when I noticed a lot of blue smoke coming from the engine when I was running at low RPM's along with it running a bit rough at idle. It's not just doing this when cold but also at the end of the day when I motor up onto the trailer when it is real bad.

Seems to run great at higher RPM's and my hole shot was good, no hesitation. The previous owner ran Mercury 2 stroke marine oil and I switched last year to amsoil the last time the oil reservoir needed a fill up.

I assume its burning too much oil but why? Possible thermostat stuck in the open position? Oil injection pump malfunction ? Other than fouling out a few plugs can I do any long term harm to the motor by running it rich or cause any other issues?

I dread taking it into a dealer not only because of the expense but also the time I will miss on the water, It's king salmon time on Lake Michigan and don't want to miss any of that unless absolutely necessary. Any thoughts and suggestions on this problem and a recommended cheap fix would be appreciated.

[UB72]

Any 2 stroke experts want to give an opinion on this??

[Alumicraft145]

17 year old motor. Good choice with the amsoil. I found royal purple to be less smoky. Eth free gas and some seafoam great way to save some problems. It's running so that's good. Fish this year and enjoy. Over the winter a good carb cleaning could be in the works. Chance to replace some 17 yo rubber parts. Nothing you can't do yourself. Oil injector might be needed to repair/replace. YouTube and ebay your friends... Hug them every chance you can!!!

[UB72]

Thanks for the reply. Yea on the 17 year old motor, no getting away from that. I bought the boat 3 years ago from the original owner and it looked in close to new condition. Just couldn’t pass it up. I have been adding to seafoam to each fill up and I’m also going to add some to the 2stroke oil hoping that will free up any sticking injectors. I’ve been running non ethanol gas as the previous owner told me he was doing the same. It probably does need a good internal cleaning and the gaskets need to b inspected. Good project in the off season as you suggested. Thanks again....

[Moonlighter]

Post over here, there are a couple of very experienced 2 stoke guys who drop past every now n then

https://www.suzukioutboardforum.com/...rd-parts-forum

[Alumicraft145]

I would skip adding oil to the gas. Just gonna smoke more. I switched from merc oil to royal purple 2 stroke and any smoke I had disapeared. An old suzuki 2 stroke would be a great project motor to have in the garage. An old bass boat dealer had a bunch in the shop years ago. Used... Guy went to jail. Bet they all got sold at some auction.

[Seaark1660]

I'd skip the SF and oil,and should try a shock treatment with some ring-free or such.Also could be carbs need cleaning.If anything,I would try and get a factory service manual for that model.

[Alumicraft145]

Suzuki motors always ran a bit Smokey it seemed to me. My friends had a few and they always idled a bit lumpy. The idle issue may be a simple idle speed adjustment.

[Ronnie]

I have 88dt 115 and on the oil pump arm where the rod hooks up there is a mark on it.Also there is a mark on oil pump housing and there are supposed to be lined up when the control box shift/throttle lever is in neutral