Old gasoline generator repairs

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Couple of weeks ago i bought two small generators they both "run" the smaller one needed an carb cleaning and now runs good, the Bosch uses an Tecumseh HS40 engine which has a blown head gasket, and only runs for couple of seconds and dies, the generator works so is worth repairing it.


the 50 hz can be "adjusted" with the throttle of the engine. speed the engine up and the hz will change. just keep an eye on the voltage cause it rises too. unless its an inverter. then you cant. but, it doesnt look like an inverter.. hard to tell.
I'm sure this engine has a blown head gasket because i can see combustion exiting when it runs, so i disassemble the pull start and the front cover wich is hold on with the head bolt and remove the head, after examining everything, looks like someone has changed the head gasket recently but hasn't clean the surfaces at all, and the material from the previous gasket was creating a gap. After the examination i used some gasoline to clean all the surfaces the carbon cleaned up pretty easy, then i used strath edges and a feeler gauge to check the surfaces for flatness, the cylinder was absolutely flat, on the head there was two spots with 0,05 mm but i managed to resurface it with couple of fresh pieces of sandpaper on a flat piece of glass, the cylinder wall looks in excellent shape the hone marks are still visible so it has has very little use.
While it's apart Ck the valve clearances they should be 10 thou slip . They not hard to do. The torque should be about 17 ft pounds on the head bolts . The longest go around the exhaust valve corner. If they aren't all the same size. The jets in the carb are probably clogged . There's a very tiny hole on an angle in the screw in jet on the bottom of the bowl plus a larger thru one . If it's adjustable start with the bottom at 1 3/4 turns out . The low side is thru the side above the bowl . Shake your float if bad you'll hear and feel the liquid inside. More help if you need it just holler
I've assembled the engine with a new head gasket started on the first pull but keeps dying after couple of strokes. I've spent an entire evening and i'm sure the carb is clean sound like is losing spark, has that hit and miss sound, can't find year of production so i don't know is it electronic ignition or it has points and condenser, it's really frustrating.
I've spent way to long working on this engine, to the point where i've disassembled the generator unit to see if maybe it was causing a problem but still sounds like a hit and miss engine,so i removed the fan shroud which is hold on with the head bolts (bed design) and remove the flywheel, where i found the date, this generator was made in 1982, which means points and condenser ignition, so i check the points and they were little oily so i clean them and set the gap at 0,5 mm, reassembled everything and it run like a champ for about 20 minutes and it started to have a miss and it progressively got worse, now i'm thinking must be the oil seal on the crankshaft geting the points oily again, should bought a diesel.
Ah yes, that slippery slope of old, small engine repair. The seal replacement should be pretty simple, if that's really the issue. Have you cleaned out the fuel tank and carb? They can often be the culprit with engines that have sat for awhile. I have faith you will get it running well. Mike
The fuel tank and carb are spotlessly clean, i'll need to spend some more time on them, the smoller generator seams to produce much more voltage 260-300v and i can't slow it down by adjusting the carb, may need to mess with the guvener.
I had a smaller generator give to me. Harbor Freight. Looked like your picture. Had the same issue with putting out 300v. Tried replacing the one replaceable component (some kind of capacitor) no luck. I ended up getting another similar generator with other issues. I combined the two make a working unit. The crrent capacity is so small it isn't useful for running more than a light bulb.
If the points are clean and no pitting or build up , chances are it's the capacitor , electronic ignition are good but points in my opinion are better . They can be cleaned and filed to run . Electronics have to be replaced at ten times the cost. If the seals leaking your points are fouling out. Seals are not costly. Forgot they gap at 020 thou. And clean with a dollar bill after setting.
With an inline spark tester you could tell. But it still can be a clog in the carb , the jets have tiny holes in the side of the brass nut if adj in center of non adjustable. Plus the low side adjustment and port my need cleaning. Sealed carbs are a pain to get clean without good carb cleaners.
Those generators have been sitting for months now but reading your experiences made me do some work on them, the smaller needs less work so i decided to work on it, first thing i did is adjust the float, had to do it 4 times, then i started looking at the speed governor, and found the bolt that is used for adjustment right under the gas tank wich after little research is adjustment for the governor, and someone has tightent it, thinking is for holding the gas tank, so i back it off also start my carb adjustment form zero and managed to adjust it to hold 220v rock steady at full load it will increase to 235v which i think is good enough, now i need to make a handle and two rubber feet for it and will be ready. The bigger generator will require some parts but i will come back to deal with it soon.
Had very little free time but did managed to make a bracket and feet for this generator, started with an 40mm flat piece, shaped it, drill and thread them and used couple of rubber stops as feet, quick job did not painted the bracket but used stainless steel allen bolts.
Today i had few hours to spare so i decided to try and fix the other generator, i know that is ignition related, so i removed the front cover, flywheel and found out the oil seal is not leaking, the inside is dry and clean, someone had used the wrong grease on the points, and they ware stuck, so i spent some time cleaning filing the points, i used very little amount of anti seize on the points, by the look this engine has very little use, i assembled everything, added fresh fuel and begin adjusting the carb, gouverner, but i'm not satisfied is not running smooth, seams to misfire every so often and fire thru the exhaust. I want to try changing the spark plug and i'll leave it to run for longer time to see if couple of heat cycles help.
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