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Hard Cranking

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Hard Cranking

Postby dennis » Tue Apr 16, 2019 5:11 pm

Working on Mastercraft riding mower. It has a 17HP Briggs and Stratton engine, mod 312777, type 0130-E1, code 980407ZD. Tried to start it and it would crank over intermittenly and stop. The starter gear would stick in the ring gear. I took starter off, cleaned it, and put it back on. I adjusted the valves as called for, .003-.005" intake and .005-.007 exhause, 1/4" past TDC on the compression stroke. No better. I had cleaned all electrical connections, including grounds, and even tried jumping the starter directly, bypassing all connections and safety switches. I took the spark plug out, and it cranked fine, no binding of starter and ring gear. I should have done this when I adjusted the valves, but I didn't...............I took rocker cover off and turned engine by hand. I did not notice any movement of either push rod before TDC to release compression. I am thinking the ACR on the camshaft is gone. Before I go to the effort of taking engine completely apart, is there anything else I should try? Also, does the ACR work on the exhaust valve or intake on this engine?
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Re: Hard Cranking

Postby 38racing » Tue Apr 16, 2019 7:49 pm

It's on the intake. When turning by hand you should see a bump on the intake valve. Did you check starter for play in the upper bushing. I repowered an ariens for a friend and he kept having cranking issues. I checked valves and new battery and upgraded charging system. Finally I checked the starter and found the wear in the bushing. A replacement starter got it fixed.
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Re: Hard Cranking

Postby dennis » Wed Apr 17, 2019 12:34 pm

Yes, the shaft was nice and solid.
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Re: Hard Cranking

Postby Arkie » Wed Apr 17, 2019 3:51 pm

Single cylinder OHV type engine.

You might try using your feeler gauge and inserting it into the intake rocker so as to take the valve lash on the intake valve to 0-.001 and test the cranking.

When I see such (which is not user friendly to diagnose sometimes) I have a clamp on ammeter and I take both voltage reading and starter load amps readings. Like 38 racing says it's very easy to over look a weak starter and bad connections in instance such as yours. I would most likely put a new or know good starter on the rig (before I took the engine apart) and if that fixes it, overhaul the old starter as a spare. You indicated you jumpered the battery and still same.
I've seen quite a few small engine starters that produced those symptoms.

I've had really good results with using starters from DB electrical.

Here is one for example of dbelectrical starter. (example only for a Briggs engine) at $27
https://www.dbelectrical.com/products/s ... gJsi_D_BwE


Let us know what ya find?
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Re: Hard Cranking

Postby 38racing » Wed Apr 17, 2019 5:28 pm

Even though you checked connection you might want to do voltage drop tests as described in here. Section 34 or 35 I think.
http://web.ncf.ca/da229/smallengine/mtd ... ical-2.pdf
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Re: Hard Cranking

Postby Arkie » Wed Apr 17, 2019 5:38 pm

Voltage drop tests.

If you find that the voltage drop seems excessive you can sometimes find a bad connection just by feeling of the connections, (even before doing voltage drop tests with a meter) a bad connection will be very hot or warm. A very bad electrical connection will fry meat and hide from your fingers so feel carefully.
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Re: Hard Cranking

Postby Walt 2002 » Thu Apr 18, 2019 8:10 am

IF you do not find any movement in the Intake valve/push rod as the piston comes up on compression stroke after piston is over half way up, no point wasting time with electrical connections etc. Observe very closely and or hold the push rod between your fingers. No movement, Compression release is bad.

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Re: Hard Cranking

Postby dennis » Fri Apr 19, 2019 11:09 am

Thanks, all, for the good information. I did a voltage drop test and it was fine. I didn't do a starter amp draw test because I figured if there was too much compression because of bad ACR, the amperage would be high, just like if the starter gear was bindiing or bad bushings. I'll try that anyway, and maybe get a new or spare starter.
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Re: Hard Cranking

Postby bgsengine » Fri Apr 19, 2019 1:29 pm

dennis wrote:Thanks, all, for the good information. I did a voltage drop test and it was fine. I didn't do a starter amp draw test because I figured if there was too much compression because of bad ACR, the amperage would be high, just like if the starter gear was bindiing or bad bushings. I'll try that anyway, and maybe get a new or spare starter.
You know briggs shop manual does have a starter draw bench test (tested off engine),right? If that passes starter's probably good, so a possibility eliminated there, which would leave compression release (as someone noted,stick a feeler gauge in and look for the ACR bump while turning engine) or sheared flywheel key,other than that you got internal binding (rod ,crank, or cam starting to seize, counterbalance seizure, bad bearings, etc) ,provided voltage drop is done right (or simply jumper cables from a good strong battery direct to starter and engine block to see if it still cranks hard)
How poor are they who have not patience. What wound did ever heal, but by degrees? - Iago (Othello Act II, Scene 3)
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Re: Hard Cranking

Postby Arkie » Fri Apr 19, 2019 3:51 pm

dennis wrote:Thanks, all, for the good information. I did a voltage drop test and it was fine. I didn't do a starter amp draw test because I figured if there was too much compression because of bad ACR, the amperage would be high, just like if the starter gear was bindiing or bad bushings. I'll try that anyway, and maybe get a new or spare starter.


[color=#0000FF]ASS[/color]uming high amperage may not be correct. If amperage draw test is too low (instead of high) is indication of a bad starter/weak battery or a bad connection that you did not find when doing all the Volt drop tests.
If amperage is too high then do a bench test of the starter off engine.
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