Engine Question


Old 08-20-03, 09:01 AM
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tecumseh rpm settings

Tecumseh repair manuals refer to microfiche for rpm settings for many of their engines. Is there a way to get the rpm specs without having to obtain microfiche, and microfiche reader? I need to know the recommended rpm settings for a Tecumseh OVRM 40 lawnmower engine.
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Old 08-20-03, 09:54 AM
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I have that OEM microfiche but it doesn't list your engine. Perhaps it's older than 10 years old---the fiche only goes back about 10 years on RPM settings.

It doesn't show this engine. Sure you have the #s right?????? What's the complete model #?
Old 08-20-03, 10:27 AM
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Tecumseh rpm settings 2

I have a little more information on the specific engine that I am looking for the rpm specs on:

It has Craftsman # 143.384192 Ser 8027A on the flywheel cover.

Here is the confusion....

Intertec's "Small Air-Cooled Engines - 17th Ed" cross-references this number with Tecumseh OVRM 40. I just looked at a Tecumseh Handbook on 4 cyl overhead valve engines, and it cross-references that same number with Tecumseh OVRM 905-42006.

Thanks for the response, Joe. I will try your references. Living in a small town, it is almost a certainty that our library does not have the fiche.
Old 08-20-03, 10:42 AM
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Using the Tec fiche I get that 143.384192 is a OVRM40-42006

I couldn't find that in the RPM chart. Here are all of the OVRM40's I found:

Model High +/- 200 Low +/- 200

OVRM40-42600A 3100 2050
OVRM40-42600B 3100 2050
OVRM40-42616B 2950 2050
OVRM40-42901A 3200 2050

I do have a Tec technician manual at home, I'll check that if I can for you.

Easier way is to call Tecumseh Tech Services at 262-377-2700 and ask. There is a fellow there named Tom who is always very helpful to me when I call.

Hope that helps---good luck and let us know.
Old 08-20-03, 10:47 AM
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generator cyles

Does anybody know of a way to check the cycles on a generator with using a meter?
Old 08-20-03, 03:13 PM
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If you could give the other part of the model number i.e. (OVRM40-?????) I could look it up on Partsmart tommorrow. Or tell us what this engine is mounted on. We could all make a pretty educated guess as to the rpm.
Old 08-20-03, 05:20 PM
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From card 30, 10/93


Low speed - 2050
High speed - 3050 +/- 150
Old 08-20-03, 08:09 PM
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More Detailed Info Requested

Hello: slim

Requesting a small favor, if you would please.

Kindly use the reply button to continue this question. If you have additional questions and or information pertaining to this specific machine, using the reply button allows the thread to continue until completed.

Doing so makes it easier for all concerned parties to follow along to it's conclusion. The reply button will automatically move the question back up to the daily list of questions. Thanks.

Kindly provide more detailed information to the questions. In doing so the moderators and members will be best able to provide you with the best possible helpful information.

Referring to your generator question, are you requesting the electrical cycles of the generator? Cycles of the engine? Kindly provide more detailed and specific information.

Regards & Good Luck.
Small Engine Forum Moderator. "Accurate Power Equipment." Small Engine Diagnostics Services & Repair.

Last edited by Sharp Advice; 08-20-03 at 08:35 PM.
Old 08-21-03, 07:41 PM
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Tecumseh rpm

Thanks for all the responses. Waiting to hear from Tecumseh technican also.

Concerning generator, I am talking about the cycle output of the generator. I have heard that for a 60 cyle generator one can plug an electric clock with a second hand into the generator and compare it to an accurate wrist watch, another clock, whatever. If both tick out 60 seconds at the same time (give or take 5 seconds), then the generator is generating electricity at 60 cycles.
Old 08-22-03, 05:47 PM
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Hello: slim

Regarding the generator cycles question. Yes. To the best of my memory, it is possible to count the cycles, as you mentioned. Of course, this method was not taught nor used in training schools. Nor is it used in repair shops.

Way back in the "Stone Age".... when I attended training classes, the oscilloscope was used. In this day, age and time period with advanced electronics, there are multi purpose hand held digital readout meters for this task.

The need for testing of cycles per second is not used often. If the engine is running correctly and set to the correct gov speed, a light will operate properly.

Reduce the engine speed and the light bulb will react accordingly. Less light will be produced. The light will not be as bright and the light will show the cycles, as it fluctuates with the cycles.

As long as the gen will produce 120-140 volts at the set gov speed, respond to the gov and run at the set gov speed, which is usually 3,600 rpms, the light bulb lights as it normally would when plugged into house current without visable signs of fluctuations, all is well.

Small Engine Forum Moderator. "Accurate Power Equipment." Small Engine Diagnostics Services & Repair.

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