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CV16S no idle


Tarheel

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Saw a Marketplace offering of an Agco Allis 516H at what seemed a good price. Contacted the owner and set a time to meet and have a look. Quite a few problems had been let out in his post including the fact that it did not run. The plastic dash mounts were broken and the deck belt tension arm was laying loose on the deck ( this was in his post). I thought about it and offered $50 less than his posted price after getting it started and seeing that the hydro was strong. There were 3 carbs for the engine. Two were from China and one came on the engine. He near broke my arm for my offer and said right out he was done with it and just wanted it gone.

 I get it home and after letting it set for a few days, started working on it. THe carb on the engine was from China and there was another just like it still in the box unused. Once I began working with it, I soon found that the Chinese carbs had a blocking pin on the throttle that worked just fine until the throttle linkage was installed. The pin was to long and the link would catch it, keeping the throttle unable to move much higher than idle. For some reason, the man had cut the wire on the fuel shut off solenoid right against the body on the factory carb,so I used the carb that was on it. Cut the pin a little over half and it now worked as it should.

 No change in the running though. Hard to start and no idle more than five seconds or so. And both only heavily choked. I cleaned the factory carb and installed it without any change in the way it ran. Lots of backfire through the intake as well. Removed the spark plug and did a propane torch cleaning. Backfire almost gone but all else remained the same. The plug brand was unknown to me and so I looked up the manual for the correct one. Factory was a resistor and this one wasn't. Installed a new one and it maybe ran a touch better. Which means pretty bad.

  I have skipped many of the tests etc I had run. Made sure the solenoid was getting steady voltage. This machine was built in such a way that part of the blower housing is under the metal of the fuel tank tray (called a bulkhead in the parts manual) So this would have to be loosened or removed to remove the blower housing. But I removed the housing bolts raised the front and it was clean under.

 By now I was running out of ideas. About all I could think of beyond was low compression from a burned valve or blown head gasket. So I pulled the head. When I removed the air guides from the sides of the cylinder, I don't know that I have ever seen so much material packed in the fins. But once the head was off, The head gasket looked almost as if it could be used again.

 I will have to check the head for warps etc and I have yet to remove the valves but if anyone has seen a problem like this please let me know. This one has me scratching my head. Thanks !

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 I made it to a parts shop out of town that had the head gasket in stock. I hope to get it installed tonight. At that point, if it still doesn't run as it should I guess I'll pull the flywheel and check the key. Thanks Brett.

 I need to make a correction from my earlier post. The "to long pin" is on the choke, not the throttle. It keeps the choke open when the choke link is in place. Sorry.

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Head gasket is replaced and no change. Plan to try and figure out how to remove the fuel tank and tray so as to remove the blower housing and check the flywheel key and ignition module.

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  • 2 weeks later...
11 hours ago, Tarheel said:

The flywheel key was fine. Still at a loss..

I have never had a CV.  But I have a CH (Command Horizontal) that gave me fits for a few years.  The compression was 150 PSI in each hole which was outstanding.  Had head work done by a competent engine machine shop.  They were warped badly & had loose seats & guides/seals.  Replaced ignition coils with the newest variant & performed extensive carburetor work.  Now I have a Keihin on the CH.  Your original may be a Nikki on the CV.  IF it is a Keihin, pay close attention to the emulsion tube & make sure there is ZERO obstructions anywhere in that tube.  Use a torch tip cleaner, repeat & repeat again.  I had the tiniest amount of what looked like gasket fiber lodged in that tube which would restrict the the flow enough so after only 2 seconds of running after startup, it ran like the biggest bag of crap in the world.  Also, the choke assembly on that carburetor needs to have a strong spring & if it doesn't, buy the choke rebuild kit for it otherwise it will crank forever without starting until you remove the air filter & hold it closed with your finger.  It is also possible on the Keihin for the CH to install the float upside down.  I didn't do this but almost did one time due to how many times I had it apart.  Get the Kohler Carburetor manual from the manuals section on this site.  You'll have to pay the $10 membership to access that section however. As far as the debris in the cooling fins, these engines went through three different valve cover & gasket changes & personally I have found every one to leak.  So mine are sealed with Ultra-Black & they don't leak at all anymore.  One final tidbit is these engines have hydraulic lifters so there is no valve lash adjustment to perform.

I realize I'm not comparing apples to apples here, but hopefully there may be something in my above ramblings that may help...

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ShaunE, Thanks for taking the time to reply. I have a feeling you may have helped more than you know.

 Everything about this CV screams carburetor problems, But after changing the carb four or five times, going through the factory carb etc and the engine running the same I started grasping at straws.  In fact, the only improvement I have seen since starting was when I replaced the new spark plug that was in it with a resistor plug.This pretty much took care of the backfire through the intake.

 I still have two new untried Chinese carbs as well as a running Broadmoor with an 18 horse CV. I now plan to remove the carb from that one and see what happens with it on the 16.

 Thanks again for your input.

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Restrictions in the fuel tank? Fuel line?? ....Old hard fuel line???

 

I fought a Prestige for 2 years before trying  a new fuel line...then all my problems went away.

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53 minutes ago, Tarheel said:

 Thanks Sam. The tank is out of it as of now so I will replace all the flex line and blow out the hard steel line as well.

If you have  some steel line you must have an engine with a mechanical fuel pump on it.??...

If so, have you cranked it over with the connection to the carb off to see if its readily pumping fuel?

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The short answer is no, not exactly. I ordered a new fuel pump and bypassed the old one, then gravity fed the fuel. I have the new pump but will test the old one before I replace it. (With the blower housing removed, I can now access everything)

 I brought the ignition coil into the house today and allowed it to warm up to room temp as per the manual before testing resistance/s. Of the three test, the first two, testing from the terminals on the coil to the laminations gave readings within specs. The third test, from the plug wire to the laminations gave a result of 4410 when the specs are 3800-4400.

 My shop has an 18 foot open front where a door would be in most. The outside temp has fallen from 41 to 37 in the last half hour so I doubt I'll find out more till tomorrow. Hope all of you are staying warm !

 Thanks again Sam for the input.

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Well, I replaced the fuel lines, cleaned all the terminals in the ignition system, and put the fuel tank etc back on it enough that I could get fuel to it and start. It will now idle without choke, if you care to call it an idle.

  It backfires, mostly through the intake but now and then through the exhaust. It will run "kind of" smooth for a few seconds, pop through the carb a few times and the rpm's will drop till I think it's going to die but then catches up and runs starting the cycle over again. Pretty much the same at wide open throttle just bigger backfires.

 My next move will be to put a timing light on it to see if the timing is changing. Then I will isolate the kill switch ground lead and retest as per the manual.

  Looking up the SAM module, I am told to use 12 707 01-s which turns out to be a DSAI replacement coil kit. (no SAM module used) To the tune of $170ish bucks.

Hopefully more later. Thanks

 

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1 hour ago, Tarheel said:

Looking up the SAM module, I am told to use 12 707 01-s which turns out to be a DSAI replacement coil kit. (no SAM module used)

Kohler has replaced the DSAI with fixed timing ignition coils. See Kohler parts bulletin PB 259. I would think if you replace the DSAI with new ignition coils, most likely your problem will be solved. 

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3 hours ago, Bill725 said:

Kohler has replaced the DSAI with fixed timing ignition coils. See Kohler parts bulletin PB 259. I would think if you replace the DSAI with new ignition coils, most likely your problem will be solved. 

  All of the engines in that bulletin seem to be v-twins. Do you know of a replacement for a Command single ? My engine is a CV16-s

Thanks Bill.

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@Tarheel Looking at the Kohler IPL, I am thinking you would replace the existing 3 terminal DSAI module/coil, Ref. 20, and the 3 terminal DSAI kit, Ref. 23, with the 2 terminal ignition module/coil, Ref. 20, P/N 12 584 17-S. FYI, I used the IPL on the SEPW website. I would verify this by contacting Kohler or a Kohler dealer. You could also talk to Jerry at SEPW. Please keep us informed.

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 Well, I finished up with all the ignition testing. There was no real change. I sat there on my brake stool looking at it and after a bit made up my mind to install yet another new carburetor. I had received two more Friday.

 I can't really say why other than having made it to a point of spending more money than I had wish to invest in this machine. As with the others, the pin on the choke lever had to be cut. I installed a new gasket, mounted the new carb. After a few spins the engine started.

 This was something like the 6th or 7th time the carb was off, cleaned and replaced or set aside and a new one installed. All without change. Until this one.

 It ran as close to perfect as made no difference.  For about 5 minutes anyway before it began spraying fuel.

 Though I am very happy to now know this engine can be salvaged, I still Don't know why it ran so poorly. At least not all. I know removing the coil and cleaning all contacts made a large difference and so I feel this was a group of problems working together. As for the carb issue ? I can understand How it could happen with one, but with all those ?  The factory carb will be taken apart yet again and this time it will soak for a day in Hydroseal. A factory kit will be installed (Including the removal of the welsh plug) and I'll try it yet again.

 That is the plan anyway.  Thank you to all who followed and or offered input.

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 Got the carb kit and put the body in the Hydroseal to soak. While I was waiting for the cleaner to work, I figured I'd pull the fuel bowl off the carb that ran so well but flooded. Pulled the bowl and found 2 small black specs in the bowl. This after new fuel lines and filter. Cleaned it up and installed it once again. Tried starting the engine, backfire through intake and exhaust.

 Messed with it a while and before long, It lost all ignition spark.

 Now I'm at a point of knowing I have to replace the ignition. It has the SAM on it. This is the coil with 2 terminals plus an outside module that controls spark advance. (12-584-17s NLA and 12-584-12s NLA)  Best I can tell, these parts have been superseded by the 3 terminal DSAI (12-584-19s NLA).

 All of the above parts are still being sold online. With the coil and module for the SAM together running over 300 bucks. The DSAI around 170 bucks. (There is an aftermarket version offered for around $30)

 On the twin cylinder Command engines, it seems there were part changes as well until at last they came around to a single terminal, Ground to kill, solid state magneto unit. (MDI I believe) I can't seem to find any info on the same being offered for the single cylinder Command engines. Does anyone know ? Thanks.

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  I found a scrapped mower with a CV16 but different spec numbers. It does have the same 2 part ignition. Got it running then changed out the spark advance module. Still no spark.

 I cut the blower housing from my failed machine into 2 pieces, front and rear. Building a machine in such a way as to make the engine "captive" is beyond my understanding. Now I can remove the head portion of the housing leaving the rear in place.

 I now replaced the ignition coil, Bolted everything back in place and the engine fired right up. Smooth as silk from idle to full throttle.  Here's to it staying that way. LOL

  The parts engine will be kept and used to try other coils starting with the single terminal ground to kill (if I can find one). If I do, I'll try and be sure to post it here and maybe save someone money and effort.

 Thanks again to everyone.

 

 

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