1999 DT25 2- Stroke Oil Injected Engine Won't Start After Service and Seafoam

[bretton28]

To start, my boat sat in storage for 7 months while we built a house and I neglected to take her out during this time. She sat uncovered in a storage parking lot. Beyond that mistake, in my 5 years of owning the boat I have never had engine issues. She's a "fire up on one start" type of engine. When I had the boat serviced they told me I wasn't going to like the outcome, that the carbs needed to be cleaned (for an extra $500), and the mechanic was worried about the cylinders. Again, never had issues with this engine. I paid them the $400 it cost me to have it serviced and told them I would figure it out. I did some research and decided to try Seafoam carb cleaner and ran it through a gas tank like the instructions read.

After two days of messing around with the boat in my driveway, IT STARTED AND IDLED with no issues. I even let it cool down for a few hours, hooked the hose back up and she started on the first key-turn with no issues. I thought I dodged the mechanic bullet and loaded her up the next morning to run out to my redfish hole. Started up no problem and ran great for about 300 yards. At 32mph it lost power (how I describe it) and at full throttle it was only running 15mph and would eventually bog down and cut off. Then I would have issues re-starting the motor all together. Fuel issue? Yes, I believe so because my primer bulb wouldn't stay hard. So I tinker with it again for another day or so in the driveway until I can get the primer bulb hard again. At this point I'm thinking its a fuel issue and once I address this I'll be fine. I put the boat in the water the next morning and it cranked on the first try but cut off when I put it in reverse. Primer bulb is soft and won't pump gas. I take the quick connect engine connector off and release it to clear any air in the line and I'm stoked, the bulb is hard and I'm ready to go fishing. The engine never started again and after working with it for a day or so in the driveway, I am stumped.

What do I have going on here? I just don't understand how I could have a great working engine one moment and the next it won't start. The worst in me wants to think the mechanic pulled a fast one on me.

[Murray]

Did you replace the 7 months old fuel with fresh fuel. Check all clamps on your fuel line, over 7 months the sun may have “dried out” the fuel lines allowing air to enter the system.

[bretton28]

Unfortunately I did crank it with the bad fuel before I had it serviced just to make sure it still cranked. I immediately realized the gas was probably bad and went ahead and replaced all the fuel lines, gas tank, and primer bulb.

[Murray]

Maybe the carbs do need a cleaning? Have the carbs ever been cleaned? You mention the mechanic was worried about the cylinders. What was his concern? Have you checked everything the mechanic did, maybe one of the plug wires isn’t seated properly? Perhaps he inadvertently bumped one of the wire connections and it’s not making contact? From the gas tank to the carbs is all new so the next thing to check would be the carbs. If you decide to disassemble and clean the carbs yourself I would suggest you get a genuine Suzuki service manual for your engine, it will have a detailed section on the fuel system and the factory settings for the carb. adjustment screws.

[Solarman]

Seafoam is good, but after the fact, it only helps a little. Your best bet, is to remove carb(s), record the number of turns for the idle mixture screw(s), then remove the float bowl, float, needle valve and seat, and other jets in float bowl then soak carb(s) for a few good hours. If multiple carbs, do one carb at a time to prevent mixing up jets between carbs (some earlier motors had different jets from factory to balance running depending if top, middle, or bottom carb.). Identify any trash found in pas-sages by wrapping carb in clean white cloth, then using compressed air blow each hole, or passage, and each jet, until all parts are clean.

When re-installing parts adjust float properly (if float is adjusted too high, fuel will run out of carb throat when running; if float is set too low, fuel will run empty in bowl at higher rpms causing motor to surge at WOT.) Then reinstall idle mixture screw(s) at service manual setting, or recorded setting (all idle mixture screws, for each carb, should be set identically - if multiple carbs).

Replace carb(s), connect water and check motor running, to see if float adjustment is good (no fuel running out of carb(s).

Carb cleaning is not difficult.

Good luck, post back if any problems.