Old turf tiger loses power once blades engage.

Coleslaw

LawnSite Member
Location
East Tennessee
Hey y’all. I’m new here but have done a lot of research on the web and this site and there is a bunch of good information but I’m at a loss. 2003 scag turf tiger, serial is 848xxxx, Kawasaki 23hp fd671d liquid cooled. Started at the end of last season, would lose power while mowing and pop and crack, and I just put it away and thought I’d deal with it this year, I assumed simple fix..not..so it runs fine but surges at full throttle , has always surged but always straightened up when the blades engage. Now as soon as I engage the blades it’s starts missing, and backfiring out of the carb, and kind of runs a little better if I throttle down while blades are on, but still not 100%, I pulled one plug wire off at a time and basically got zero change, also the unit has 2100 hours, to start with I pulled the coils and did a resistance check had one at 16k ohms and one at 20k ohms, so I ordered coils but just replaced the highest resistance one, (also the shipping was delayed on one so I just installed one and planned to do the other later), no change, removed and cleaned carburetor thoroughly, brushed all the jets out after soaking in carb cleaner, installed new fuel shut off solenoid on carb, I got the surge to go away at full throttle but still no power with blades on, still backfires. I changed fuel filter and blew out gas lines, adjusted the valves, and still nothing.i hooked up a inline spark checker and once I full throttle and engage the blades it seems like its spark cutting, I can see the light go from almost solid blinking to skipping once I engage the blades.I plan on rechecking the valve adjustment again this weekend, but I’m at a loss. I’m a mechanic by trade but don’t fool with small engines that much. I have owned this mower for 10 years and mowed commercially with it for 8 years. It’s been great, no major breakdowns, so I hate to give up, but all my other mechanic friends are also at a loss as well. Can anyone help? I know how hard it is to diagnose something without standing next to it but I’m struggling here. If anyone needs more info just let me know. Thanks in advance.
 

Justin Hightower

LawnSite Member
Location
western Ky
Sounds like carb issue. Those Kawi carbs can be a pain to clean. Some of them I’ve had to pull Welch plugs to get back right even after an hour in ultrasonic cleaner. Not sure if it’s possible but try spraying it with starting fluid while running with blades on. Not a lot just a small quick must see if it clears up
 

Breezmeister

LawnSite Gold Member
Location
South Jersey
i hooked up a inline spark checker and once I full throttle and engage the blades it seems like its spark cutting, I can see the light go from almost solid blinking to skipping once I engage the blades.

Couple thoughts. Was the spark problem on the new coil or the old one, or both ? I would disconnect the kill wire to the coils, then run at WOT with blades on to see if the problem goes away. If the problem goes away, then the problem could be some where in the wireing loom or a safty going bad......



I plan on rechecking the valve adjustment again this weekend, but I’m at a loss. I’m a mechanic by trade


Then you can do a compression and leak down test, get an idea of the health of the engine.
.
 

danell10

LawnSite Senior Member
Location
saginaw, mi
Sounds like carb issue. Those Kawi carbs can be a pain to clean. Some of them I’ve had to pull Welch plugs to get back right even after an hour in ultrasonic cleaner. Not sure if it’s possible but try spraying it with starting fluid while running with blades on. Not a lot just a small quick must see if it clears up
I had a 17 HP Kaw that blew out its Welch plug and then ran similar to what you described. I never heard of a Welch plug until I took it to a shop to be looked at. They replace the plug(on bottom of carb) and all was well again.
 

Caledwen

LawnSite Senior Member
Replace the ignition coil
That’s always what it is on a kawisucky
It’s running on one cylinder[/QUOT
I was going to suggest that as well. I recently had to replace both of mine had similar symptoms to those described.
 

danell10

LawnSite Senior Member
Location
saginaw, mi
Yeah, coil too! When I got my Turf Tracer with a Kaw in 2008, one of the coils failed in the first month, I'd replace them both and check the Welch plug.
 
OP
C

Coleslaw

LawnSite Member
Location
East Tennessee
Thanks y’all. I’ll check on those things as well. I piddled with it a bit last night, I checked the air gap on the clutch and checked the resistance on it as well, everything ok, also found one of the fuse holders next to the seat was getting super hot. I traced the wire down found it to be the charging wire I guess, goes straight into the rectifier. I checked the resistance on said wire and had .01 ohms. I had thought maybe something was wrong in the clutch circuit causing it to drop power out. I still don’t have a clue. Haha. I’ll get that other stuff checked and report back. Thanks again.
 

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