DF 50 stalls at idle with cowling on

[Rhode Island Red]

I need help and advice please. My 50 HP Suzuki four stroke idles fine with cowling off, but when cowling is replaced the engine begins to slowly sputter then dies. Interestingly, during the sequence where performance is going down hill if I take the cover off the engine idles perfectly again almost instantly. I have checked the air vent in the top rear and that is clear, I can touch my fingers between inside and out. Once I get above idle the engine runs at cruise fine, although there are stretches where the check engine light flashes along with the warning horn sounding. These warnings come and go with no explanation. Since the boat is kept at Block Island RI there is no Suzuki dealership close by, and the folks that sold me the engine have closed. Any ideas out there? Thank you!

Thanks to everyone that has read my original message. The confusing thing about the symptoms is that if they occurred because of a fuel problem then why wouldn't the stalling continue when the cowling is off? Also, once the engine gets going it runs nicely at higher RPM, then only shuts down when brought back to slow speed and then konks out at idle.

I am desperate and hoping that someone can atleast give me a few ideas that I can share with the local tech that is unfamiliar with Suzuki. John

[tommybe1]

I just replaced the fuel lines on my df50, the ones I ordered were alot thicker and I noticed the cowling was slightly pinching one of the lines, something to check, weird problem. good luck

[Rhode Island Red]

Tommy, I deeply appreciate you taking a stab at my issue. The problem is not likely fuel because when I run at cruise 3800 Rpm the engine steams right along. Only at low speed do the symptoms begin and disappear the instant the cover comes off. I got up enough guts o call a local Yamaha dealer and the nearest Suzuki service center. What I learned is that the annoids or sacrificials inside the engine need be changed yearly because these engines are extremely susceptible to electrolysis. Since to my knowledge they have never been changed, because the selling dealer went out of business and I have been using a non certified technician, the fear is that the exhaust has developed a leak spilling into the cowling and suffocating the engine. If true this will be a hard lesson, the Suzuki service Manager was fantastic! His opinion was the engine could need a major rebuild. Lesson is don't skimp on the expert service, the annoids are easily replaced and inexpensive, but I just assumed that when I performed my year end service that this would have been taken care of. Anyway, I'll post the result, it could be ugly. But anyway you were the only member willing to take a shot at helping so I sincerely appreciate you taking the time!

[Rhode Island Red]

Tommy, closest Suzuki dealer has an awesome Tech. I called their office, he diagnosed as a leak in exhaust. Engine is 2005 and annodes were never changed because dealer that I purchased the outboard from closed up and my mechanic that performed year end maintenence was unaware that the sacrificial annodes needed replacement yearly. The authorized Suzuki Tech says that he is 6 for 6 in nailing the issue, a hole on the exhaust. He says the repair cost may exceed the value of the engine because requires a major overhaul. Not good news, but a lesson for everyone out there, change the annodes every year, pay now or really pay later! Thanks for taking a stab at solving my plight. RI Red

[Rhode Island Red]

To clarify the Authorized Tech blamed electrolosis as the culprit! He was firm in the belief that Suzuki engines are particularly prone to problems due to electrolosis, and that if the annodes are not changed religiously to expect the worst.

[SpookySuzuki]

Hi there, Rode Island Red. I am 99% positive it is me that ended up with your DF50. I won it on an Ebay auction last September. The Yamaha Dealer in the RI area that auctioned it gave me the background on the engine described your situation to the letter.
I just got the boat in the water a couple weeks ago and sure enough it ran terrible with the cowl on. After some searching the web, and read the many posts regarding the anode corrosion issue, I
found the hole in the spacer block. I was actually glad! Problem discovered.
For now, I just throughly ground and cleaned, then used JB weld to seal the hole. The engine now works beautifully. Once I adjusted the idle air control back down that is.
When th JB lets go, it will get welded up properly. That is a bigger job...
i was suprised at the power of this motor. Faster than my buddies Merc 4stroke 50, which i thought to be the benchmark in its class.
A footnote. The Yamaha dealer that sold me the motor was fantastik! They were very upfront in disclosing the condition of the engine. The shipping charges were downright cheap. The engine was packaged up as if it were a brand new engine. I would be happy to give them my business.
cheers

Tom

[pandilucciano]

Hi there, Rode Island Red. I am 99% positive it is me that ended up with your DF50. I won it on an Ebay auction last September. The Yamaha Dealer in the RI area that auctioned it gave me the background on the engine described your situation to the letter.
I just got the boat in the water a couple weeks ago and sure enough it ran terrible with the cowl on. After some searching the web, and read the many posts regarding the anode corrosion issue, I
found the hole in the spacer block. I was actually glad! Problem discovered.
For now, I just throughly ground and cleaned, then used JB weld to seal the hole. The engine now works beautifully. Once I adjusted the idle air control back down that is.
When th JB lets go, it will get welded up properly. That is a bigger job...
i was suprised at the power of this motor. Faster than my buddies Merc 4stroke 50, which i thought to be the benchmark in its class.
A footnote. The Yamaha dealer that sold me the motor was fantastik! They were very upfront in disclosing the condition of the engine. The shipping charges were downright cheap. The engine was packaged up as if it were a brand new engine. I would be happy to give them my business.
cheers

Tom

Hey where are those located??