186f (Yanmar L100 clone) performance mods

[redlined_b16a]

First off This forum has the most info and people who know real info on these engines.So I have come here looking for general info on performance mods that can be done or experimented with.

I have a Atima 186F engine that was on a generator that go struck by lightening at 41 engine hours.Melted the starter and everything else electrical fried.
I fabbed up a pull starter,cleaned fuel injector and pump.Fired right up after a couple years of sitting.

Im looking to squeeze just a lil power from the engine.Right now I can only run the engine not loaded and she seems to run rough and stumble at higher rpm's.No smoke.

Im at sea level so what should the shims for the injector and pump be set at?For sure I have 3 pump shims.The injector has a small internal spring inside,would adjusting this spring tension allow more fuel flow?Would the tiny injector nozzle holes allow more flow?

Im not looking into turbo's at the moment cause I haven't found a turbo build yet that states performance was improved.Found a few claim it was sluggish due to not enough fuel delivery.However I did read about airpump superchargers a lil here.Seems interesting but I could not find a source for the pump.

Is there any know performance pump or injector made on the market?

Will tighter valve springs help this lil engine out?

Im looking for this engine to be placed in my mudboat,I currently have a 13hp Kohler command gasoline.From what I can gather on the internet these lil engine are comparable to 3-4hp larger gasoline engines because of the higher lower rpm torque and flatter torque curve.

You guys/girls have the most advanced Yanmar/clone info avalible,Thanks for the help in advance.Since I have found this forum Im now looking for a donor bike to do a diesel swap project.Im fond of the 70's-early 80's Japanese bikes though.Any other vintage brand round here are scarce

[gilburton]

The 186F would suggest it is the 10hp version.
Just a thought but does this one have a fuel cut off solenoid and if so did you check that out as well??

[redlined_b16a]

No fuel solenoid,all manual.Kinda strange because it has the oil pressure switch but no fuel cut off.The 186f is the 10 hp model.
If I figure out how to get more fuel delivery how do I get more air into the combustion chamber?Is that where playing with the fuel timing comes in?

I guess I'll wait to load it up in my boat before any mods to look for black smoke.

[redlined_b16a]

It also appears that from reading thru the threads here The generator engine has a different fuel pump than the regular engine pump because the generator pump isn't variable.Its designed for full speed use.

[gilburton]

To be honest parts for these are ridiculously cheap so assuming there is no problem with your head/valves/piston I would just buy a new pump and injector and then you know these parts are good as it certainly sounds as if you have a fuel problem.
If indeed the pump is only made for high revs then putting one in that will respond to variable conditions can only help.
I've no doubt someone who can advise you of your shim settings etc will soon respond as it's late afternoon over here so probably most people haven't seen your post yet.

[coachgeo]

There are threads in here where people have altered the IP linkage in similar engines to make it work for a bike. If yours will not take a load then there is other issues cause an genset engine is designed to feel a load and up the fuel to accommodate thus keeping constant RPM and constant volt and amps

[redlined_b16a]

I have never loaded the engine as of yet,Only ran unloaded.Before I can use the engine in my boat I have to cut the tapered portion of the crankshaft off.Remove the crankshaft and get it keyed by a machineshop.Remove a output shaft from my transmission and get that machined and keyed.Then fab a mount to install into my boat.All the machine work is free.But I may just pony up the dough and buy a 1" keyed straight crank,hook the motor up direct drive like the current one is and load the motor up first to get a starting point.

worst case I have to spend about $150 on crank,gaskets and a variable fuel pump.The engine was free......the best price.

[redlined_b16a]

I got the engine from my brother who got it from the original owners.They claim that the changed the fuel pump cause It wouldn't start,so perhaps the pump I have is a variable one.How can I tell if it is or isn't?I only see one ebay add in the u.k. that list a variable pump,a million other pumps not listed as variable.Does anyone have the variable pump part number.

Here is pics of my engine.
I made a pull starter cup out of dolly rims......It works.

[redlined_b16a]

here is a vid of it running,when reved hig it seems to miss.....bt not loaded

[pietenpol2002]

While it's marketed as a 10 hp mill, it's realistically closer to 9 hp. Regarding the crank, you might consider utilizing a keyless bush on the straight portion of the crank and save yourself the work and expense of swapping out the crank. There's plenty of material to mount the bush on. It would then be a simple task of bolting a coupler between the bush and your trans. The process in discussed in several different threads here on the board. The tapered portion of the crank can then be easily amputated with your angle grinder. That said, if you have ready access to machining services, some builders have machined a tapered bushing to bolt directly to the your existing crank.

We may be talking about 2 different things with respect to "variable" injection pumps. Generator engines have governor/fuel delivery linkages designed to maintain 1 speed. And thus, the RPMs are not variable. Modifying the linkage to provide for variable RPMs is a simple task. The injection pump however is quite variable in the amount of fuel it supplies in response to the demand from the engine. I should note that the early constant speed generator engines had a less refined pump than the later variable speed engines. However, they tended to have a greater negative impact on idling than at higher speed. Yours would appear to be one of the earlier renditions with the single bolt rocker boss.

The rule of parsimony would dictate first identifying the source of your high speed stumble. Certainly check that you have clean fresh fuel and that there's an adequate supply unimpeded by a clogged filter or the like. Confirm also that your hose clamps are tight so no air is being introduced into the fuel system.

With regard to your desire for greater fuel delivery, the existing pump is quite capable of supplying all the fuel the engine can manage, and then some. That process is nicely detailed on the Riding on Salad Oil site http://www.altmann.haan.de/riding_on_salad_oil/ with the explanation down the page a bit. There are also numerous explanations and pics/drawings found here on the board as to the proper setup for your engine.

Before attempting to supply greater air to your engine you may wish to open up the exhaust a bit. It is reportedly the most restrictive element of the head. A more freely flowing exhaust pipe would be in order and some have resorted to mild porting of the head.

[redlined_b16a]

Thanks for the responses.

I have run the engine with no load at variable rpm's slowly increasing it until near full speed.It does accelerate fine.

Yes it does have the single bolt rocker arm,I read some placed that its a bad design.

[pietenpol2002]

Yes, apparently the single bolt rocker arrangement has been problematic for some. It seems the solution is to remove the locating pin and bore both the head and rocker fixture, tap the head for threads (ideally it would be a helicoil) and add the second bolt (using Loctite for both). But, perhaps not needed unless the single bolt design gives you trouble.

Two other things to consider with your high RPM difficulties. A restricted air supply could produce the symptoms you report. Have you tried it with the air filter removed? And then, given that it was liberated from a generator, it could well be the victim of wet stacking. Generators are notorious for wet stacking if they've not been run under sufficient load. The inadequate combustion chamber temperatures result in unburnt fuel producing carbon deposits displaying the very symptoms you've described. The solution is to put the engine under 70-80% load for a sustained period of time. The results won't be pretty as the carbon deposits being discharged will produce quite the fireworks. Might want to remove the muffler. Google wet stacking for further info. For what it's worth.

[redlined_b16a]

Since we are talking mufflers here will it hurt the engine to have a less restrictive muffler?Something Like a straight pipe,no muffler.Next week I will be home to put the engine unler load in my boat.If I ride in hard clay bottom the engine will see a hard load.

[pietenpol2002]

Straight pipe shouldn't be a problem. See below.

http://www.advrider.com/forums/showthread.php?t=598776

And Youtube vid of the same bike.

http://www.youtube.com/watch?v=ScfluRcMbs8

[redlined_b16a]

Happy to report The engine is in the boat and I really loaded the engine today.

I put the boat in the water running it against the warf at full throttle............People nearby thought the boat was on fire.It was cool to see a boat roll coal.
If I run the engine at lowspeeds such as a no wake zone for about 10 minutes it wetstacks and sometimes runs rough but speeds up to full throttle fast and pumps out black smoke for a few seconds.

The real test was in mud,its what the boat was designed for.I ran effortlessly in about 1/2" water,Pure mud was flying from the stern.15mph in deep water and about 20mph in shallows.I tried to get stuck so I can load the engine.

Overall Im very pleased and will post a pic or two of the boat.
Engine runs strong at any speed,Im turning an 8" prop probly 6" pitch.

[redlined_b16a]

will the cat converter and second muffler hinder performance?with one single muffler its a lil on the loud side.

[pietenpol2002]

You sure it's a catalytic converter? Diesel engine oil containing zinc (more specifically ZZDP) will dispatch a catalytic converter in short order. Which is why modern automotive engines and oils (post 1988) were developed to function in the absence of zinc. But our little Chinese clones containing parts cast and machined from butter, desparately need that zinc.
Back pressure from a muffler is likely far less restrictive than that 90 degree turn that exits the engine. Any of Louisiana's 30 Tractor Supply's stock a nice selection of replacement tractor mufflers for small displacement Ford, Allis etc.
And we don't just want pics. We want vids. Some of us struggle to conceptualize how a boat can displace mud.

[redlined_b16a]

In the engine pics I posted. Bolted to the engine is what looks like a cat converter.looking inside the pipe it has the tiny ceramic squares, looks just like a cat converter.I wont be able to hit the water again until another 3 weeks.youtube search mudboat or mud motor.tons of vids.

That 9 or 10hp clone is an animal in a mudboat.Is there any link to the mod you guys do to the throttle for the motorcycle use?

Also a write up on adjusting the rev limiter screw on the governor.

[redlined_b16a]

Pro Drive Outboard Demonstrating Full Power Rever…: http://youtu.be/xiKP3UOXLLM


Not mine or my style of set up.but really good example of a boat in mud