if the injector is atomizing properly, that is it is spraying a good pattern and not a squirt and dribble

if that is true and the engine is over fueling the rpm will rise in relation to the amount of fuel being injected

i am not familiar with your particular unit, so i ask the following

is the intake unobstructed?  all the way to the intake port?  no rubber parts/couplers collapsing in the intake air cleaner piping
(this might not apply to yours but i have seen rubber elbows collapse and stall an engine)

from what you post, the engine does not stall or exhibit this stalling problem when under a 1500 watt load?  but does with a higher load?

another thing to check would be the output voltage under load, does it stay stable and  even after the problem first starts to show its
ugly head? 

does it slowly taper downward just a bit, but stay relatively stable until the engine shows signs of having trouble running?

or does it run relatively stable, and then show a sharp or sudden reduction in voltage, (doesn't need to be much, but under a fixed load
i would expect perhaps a small and slow droop in voltage under load, but i would not expect a sudden drop of even 5 or 10volts.

without load, i am to understand that the thing will run and not show signs of stalling, run just fine, smoke consistent in quality/color?
and under 1500 watts or less 1.5kva it runs fine, smoke consistent in quality/color?

under a heavier load of say 1.75kva or 1750watts, the problem shows up?

how about this

check the voltage at 1.5kw load, let it run for 20 minutes or so and chart the output voltage

then raise the load and let it run for 20 minutes of so and chart the output voltage


what i am getting at is this, coppers coefficient of expansion is fairly high, and copper windings in the stator core are wound tightly
and packed closely together, it might be that under enough load the copper gets warm enough to expand enough to press against another winding and breakdown the insulation/varnish so that there is a short.

the reason i am on this track and wanting you to eliminate the possibility is based on the following

sometime back in '07 i having built a changfa s195 into what i referred to as a trigenerator, it drove a pair of prestolite/leece neville 110-555-jho alternators 12volt nominal, i was working with running one of the alternators in 24volt nominal operation (28.8vdc). under one of the tests the 195 exhibited very similar problems to what you are experiencing.

the problem was related to the alternator having been fitted with 30v avalanche diodes and when i ran the system up to 28.8 and as things warmed up the voltage at the alternator bumped 30volts... this in turn basically created a short and made the alternator into a really effective electric brake. 

the 195 would lose rpm, but not quite die, the reason was as the rpm dropped the alternator would drop below the 30volt avalanche threshold and allow the engine to speed up, and of course this cycle is very fast and in effect just dropped the rpm to reach equilibrium and not stall the engine.

so basically the stator was shorted by the avalanche function

now you don't have that problem, but the theory of operation is similar in that "if" you have windings in the stator that are old enough, and have broken down insulation, they might well start to short under load when things warm up, and because the short cannot go away like my alternators did (below 30vdc the avalanche shuts off and so does the short), then it continues the loading until the engine stalls.

i am not suggesting tearing down the genhead, what i am suggesting is removing it as a possible problem by running some voltage tests, and if you have one of those laser temp guns, check the stator core for hot spots, that is if you can get to it fairly easily.

if you don't have a laser temp gun, just feel around the outside of the generator housings to see if anywhere seems warmer to the touch than the rest of the housing, you might feel a hot spot that way?

it just seems really odd to me, that the engine is actually seizing up, i would expect other problems caused by that happening, and none of them are good.  and i don't think that 1.5kva of load would be enough to cause a problem, but if there is a short the actual load would be much higher then 1.5kva or even 1.75 for that matter.

most times it is the simple things that we overlook when it comes to diagnostics, so carefully make a list and check off everything, when it comes to hard to find problems, more info is always a good thing.

fwiw
bob g

i have a 3.5 hp mini petter, indian manufacture
still in  partial crate, never been fired since it left india,
that is if it was even fired up then.

water cooled version.

not sure where you are located, this would probably have to be picked up
here in central kansas, my back is such that i can't do much to get it shipped

bob g

back up and working now, thanks for your patience

bob g

in mainland china and the orient in general i would not surprise me to find out there are over 100!

bob g

back when they were used in trucks, pre '85 or so, detroit would not warranty for oil consumption until it exceeded 1 gallon per 800 miles

1 gallon in 4000 is very good in my opinion, most never came close to that good even when new.

as for how long will it live? no way to tell other than it should have another couple hundred thousand in it given the oil consumption criteria and if it is well maintained and not abused.

problem is there are any things that can take it out long before then, it could be 200k more miles or it could be 10k more miles... all it takes is a liner o-ring failure and antifreeze contaminating the oil, lack of attention and you loose bearing material pretty quickly... or  a bad water pump, blown coolant hose and a severe overheat and the engine is then due for an overhaul.

in my opinion, if you have no records of the last overhaul, or if the thing is 20-30 years old , or some combination, then you really can't say how long it might last.

bare minimum, if i knew nothing of the records of the engine, i would at the very least
drop the oil pan and have a look at the brgs, pressure test the coolant system and check for weeping around the bottom of the liners (*more on this below)  and if all looked good button it up... then replace the water pump even if it shows no signs of leaking, and replace all the upper end coolant hoses at the very least (they are the ones that run the hottest and under the most pressure and likely first to fail)

lastly (because i forgot to mention)  if the brgs look like they have a bit of wear, i would replace them while your in there... brgs, hoses and waterpump, along with new tstats are cheap insurance.  minimum oil pressure hot at idle is around 5psi, so don't freak out if it isn't much above that.

also... take a look at the air box drains!  the tubes below the air ports along the side of the engine right below the inspection covers... make sure these tubes are open to the ground and not connected back to the pan via some sort of check valve thing. there is a tube at the rear of the block on both sides and these must be open to drip on the ground...

reason being the 92 series has water above the ports on the liner, if the liner orings start to leak the tubes must allow this coolant to drip on the ground, else it will end up in the crankcase and brg failure is the end result. 

there were a few years of production where detroit used the check valves and ported the tubes into the crankcase!!  this proved to be a very costly mistake for detroit and they put out a service bulletin calling for the removal of the checkvalves and porting the tubes so that they could leak on the ground.

not all of those engines got the alteration/recall done on them, it might be this engine has them and that would be the first thing i would remove.... if the engine has them and you remove them, then yes you will get some oil on the ground where you park, that is just part of the fun of living with a detroit... far better to deal with some dribbling than to have crankcase contamination and bearing failure in my opinion (and also in the opinion of detroit)

*getting back to checking for seepage at the liner packing... the only way to really check this is to pressure test the cooling system, and leave it pressured up for a couple hours, both hot and cold test, and look for drops on the ground under those pee tubes (airbox drains)  if you have any signs of antifreeze on the ground, you must then remove the airbox covers from the side of the engine and check around the liners above the ports for seepage of coolant... this can be quite a challenge because access is tough in most cases, so maybe one of the new fangled video probs could be pressed into service to aid in checking thing over...

if you see no antifreeze seeping around a liner, but coming down under the ports along the bottom of the airbox, and if the engine is turbocharged it will have an intercooler, which might have an o-ring failing or a crack in the cooler core itself. 

in any case, there should be no signs of antifreeze coming out of those pee tubes.

having said all that, you might see some water droplets under some conditions, such as cold running and very humid days, the water in the air can condense (will condense) and show up with the oil droplets on the floor... don't worry about that source of water, it is normal
 
you do a taste test to determine if it is water or antifreeze (yes i know folks are gonna gag on this one)  just dip the end of a finger into the water and touch it to the end of your tounge, if it isn't sweet, but just tastes like oily water your ok!  if it tastes sweet it likely has antifreeze leaking somewhere.

in closing these engines are quite durable and can provide a long service life, given decent maintenance and driven properly.. don't overheat them, and don't allow them to run unloaded any longer than is absolutely necessary... use straight weight oil only, minimum 30weight, preferably 40weight series 3 diesel oil only... do not use multiweight oil unless you want to see the oil consumption to escalate.

and never ever ever let any mechanic do any sort of adjustments, valve/injector setting, rack setting or even lift a valve cover and definitely never the governor unless he is an experienced and certified detroit 2 stroke mechanic! 

water pumps, hoses, tstats and even bottom end brg replacement a qualified diesel mechanic should be ok there, but don't let anyone mess with the top end.

doing otherwise and 999 times out of 1000 the engine will not run right till you get it to the guy that should have been working on it in the first place.

good luck
bob g

 

i have seen these angle drills at many pawn shops, they generally always work and can be bought reasonably...  never pay the sticker price, dicker with them and you can usually get around 30-40% off the listed price.

failing that, harbor freight sells some smaller angle drills, however the are limited to 3/8 inch

they also sell a three piece step bit set, the smallest of which is 1/2inch on the largest step

these bits really work well, just keep them cool with a dribble of water and the drill right through.

great for enlarging holes

good luck
bob g

sorry i got way behind with registrations over there, and it looks like they are piling up here too.

you have been cleared and should have an email to that effect, if not let me know.

looks like i am going to be busy this weekend, clearing the applications

bob g