'04 Suzuki DF90 Dies

[caylorray]

In early 2008, on the way back to the dock after boating all day, went down to idle to waiting for a friend to get truck/trailer, and the motor died. Took several attempts and a few minutes waiting for it start back up.

This happened during a couple subsequent trips. Realized just letting it sit for a few minutes and it would start back up, so didn't stop the trips. Once above idle, it ran like a champ. Also ran just fine on muffs once back at home.

Deployed for year and after getting the boat back out, replacing the high-press fuel pump (pump went bad from sitting for so long), and also replacing the MAP sensor (only thing I could think of to fix this problem), the problem seemed to be fixed. Put the lower unit in a tub of water to simulate being in the water, and it ran without dieing, although idle RPM was a little low.

Thinking I had the problem fixed, dropped it in the water today. Was running just a little sluggish at first. Parked the truck/trailer, came back to the boat, and the eng had died. Could eventually get it started back up, but only keep it running well above idle. Once back to idle, it dies.

Have visually looked the motor over. There are no exhaust blockages. Fuel pressure is good. Heck, the eng, and almost everything on it, looks almost as good as when I bought it new. Running on muffs it runs as it did when it was new, purrs like kitty.

Before taking it to a mechanic, I'd really like to exhaust all possible solutions I can. Any thoughts?

[Socalfisherman]

I believe that your IAC motor has gone bad. Had same issue with DF250. The hole on the side where the IAC is located is open to the elements. IAC stands for Idle Air Control. This of course does control the idle and if not working will cause stalling or low idle.

[Socalfisherman]

I forgot one thing. Did you try adjusting the air adjustment screw on the throttle body? Try this and see if maybe it is turned in to far.

[caylorray]

Thanks for the advice.

Removed the IAC valve. Ohm checked it, and it reads 10.2 on a DMM. Plunger doesn't appear to be sticking. Moves freely, although not real "springy". Not sure how responsive the spring is supposed to be. Centers back up when moved in either direction. Was a little build-up of what appears to be carbon. Cleaning it now. Gonna drop it in the water this evening and see how it runs.

Couldn't locate an adjustment screw on the throttle body. Even if there is, not sure I want to mess with it. At least until I've run out of options. Motor has been running perfect for over 600 hrs of use. Just can't see that suddenly being out-of-adjustment. I've been wrong before though!

[abbeck76]

Hey there,
I had a similar problem with my df90 about a year ago...it ended up being a hole that corroded through the engine holder which caused exhaust gases to fill the engine hood and starving the motor of fresh air. I would run the motor with the hood off to see if the problem goes away and check the engine holder for corrosion/hole.

[caylorray]

abbeck76,

Funny you should mention that. After cleaning the IAC valve and reinstalling it, I decided to remove the lower cowling to inspect the engine holder as I'd read about it on another forum. And there it was, a big 'ole hole right under the lower plug on the left side. Repaired the hole using JB Weld, dropped it in the water today, and the idle problem was gone!

[abbeck76]

caylorray,
Well I'm glad that resolved the issue....I chased my tail with the same scenario last year and used JB weld also. So far so good, but I will say that it was very disappointing considering my motor only had 250 hrs on it at the time. I even broke down and took it to the local dealer and they did'nt find sh%t...it was through internet research that I stumbled upon it and fixed it myself. Good luck

[Stellios andreas]

Good day,
While my engine was running smooth, I tried to fix the trim. By the time I pressed the trim button my engine died giving me beeps and giving me a "check engine" alarm. I could not started again.. any idea what could have happened?