1987 Suzuki Dt 75 Starting issue part 2

newt5005

Seaman
Joined
Nov 15, 2004
Messages
51
The engine runs.
O.K., just barely, maybe a little better than barely. Runs a little rough. I've convinced myself it's the carbs for a couple reasons. It wont stay running at an idle unless I run the throttle stop (idle adjust) up and turn the idle speed to around 1,000RPM and it wont start at ALL unless I give it a shot of starting fluid, unless the motor is well warmed up.
It throttles up (seemingly) fine and planes the boat well, stays on throttle as well. The key-push actuates the choke solenoid and rolls the carb plates into "choke" position.
Assuming I'm on the correct path (input appreciated at this point) What do I look for after or even before taking the carbs off?
I cannot find any info on the choke system or circuit in either of the two manuals I have, only how to check the solenoid.
I already know to carefully inspect the needle for profile and floats for fluid, as well as ports for cleanliness. Is this choke system only built to restrict the air intake, or is there anything else to it? I have heard these DT series motors are a little on the cold-blooded side, but the air temp here was in the 60's and 70's when having these issues. When using fluid to start, on shot is all it takes and it doesn't die, when firing off the bottle (can).
As a bonus, I have no history with this motor as it's new to me. I will have a carb sync gauge and a set of rebuild kits in the mail soon, just gathering info ahead of time.
 

bmc02

Recruit
Joined
Jul 21, 2012
Messages
5
Re: 1987 Suzuki Dt 75 Starting issue part 2

Hi, I'm new to boating but I have spent a lot of time with my 82 dt115 since I bought it last year. The best starting procedures I have learned is choke and throttle for first startup. Every start after its warm I use no choke and no throttle. If I don’t follow those procedures it has a hard time. the right procedure alone can have a big impact I found.. For checking the choke if you push the choke button they should close. Verify by looking at linkage and/or look with front cover removed. The buzzer (if equipped) and solenoid click is not enough confirmation. My choke would often stick and not close. there is nothing else to the choke, just limits air to cause a rich condition for cold starting. As far as the carbs, just rebuild them first then see how it does and go from there. With no history on motor (like I had) it should be at the top of the to do list. My engine ran like crap when I first got it and like yours was very hard to start (starter fluid required). Turns out one of the carbs was completely clogged. So get the rebuild kits, break each one down keeping track of all the parts. I always take a lot of pictures in case you forget how something goes. But these mikuni carbs are pretty simple. Soak each disassembled carb and all pieces in a gallon of carb cleaner. I left ea. carb in for at least a day. Then spray liberally with carb cleaner, especially through the jets and passages. Check the float level when putting back together and set the idle screw. Turn in until lightly seated then back out the specified amount (1.5 turns on my 115). I always like to put in new spark plugs too which can help to diagnose. Like a brand new plug that is still new after running tells you that cyl isn't firing. Also before anything else you should do a compression test on ea. cyl if you haven't already, otherwise you may be wasting your time... Good luck!
 
Top