B&S 331977-0010-G1 loud bang, smoke from oil filler, and won't start - Lawn Mower Forums : Lawnmower Reviews, Repair, Pricing and Discussion Forum
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post #1 of 2 (permalink) Old 03-24-2019, 12:58 PM Thread Starter
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B&S 331977-0010-G1 loud bang, smoke from oil filler, and won't start

Hello, homeowner on 2.5 acres and the Toro ZTR16-44 I inherited (ran fine the first year, this was the second year) with the house was idling while I jumped off to clear some brush, and stalled. When I started it it gave a loud BANG, and then wouldn't turn over again. Checked oil (which it had) and lot's of smoke poured out the filler neck. The previous owner had a connection and got me a replacement, but I need some advice on where to start with the engine swap:
MODEL 331977 33S877
TYPE 0010 G1 0002 G1
CODE 130220ZD 160916ZD
CC 540 540
HP 19? 19

I was told the old has 9amp VR and new has 16amp VR, so i'll need to use the old one, and use the old starter.

I've tinkered with my old car, but would appreciate some direction on how to tackle this swap.


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post #2 of 2 (permalink) Old 03-25-2019, 12:36 PM
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I wonder if it blew a head gasket and caused pressure build up in the crankcase. If it was idling at a low RPM I can't see it throw a rod or valve guide. These OHV engines can blow head gaskets if allowed to overheat especially when dirt and grass debris (and mouse nests) builds up under the engine cover(shroud, blower housing). Often the thin strip of head gasket material between the cylinder and the cavity where the pushrods go through that goes into the crankcase blows out and combustion pressure enters the crankcase and causes problems.

As far as the swap the only thing I can see as a possible issue may be that if you put the 9 Amp regulator on the new engine it still has the 16 amp or so alternator (charge coil) under the flywheel and possibly if the battery gets low plus the inrush current of turning the PTO clutch on could cause the current to exceed the 9 amps of the regulator. On the other hand, if you leave the 16 amp setup in the charge rate could be too high for the size battery in your mower (could always go to a larger capacity battery if it fits).

Other than that the swap should be straight forward, make sure the length and diameter of the shaft is the same, and you may need to reroute the throttle and/or choke cable which could require replacing the cable if too short or cutting it if too long, also the wiring connector(s) may need to be swapped or replaced. The Toro website should have a downloadable manual with the wiring diagrams.

As far as the original engine, maybe someone here can provide guidance but of it is a head gasket it seems it's not too difficult to replace and there are a number of Youtube videos on how to do it.

Good luck.

AKA Blosumsno

1978 Dynamark 832, 2016 Cub Cadet XT2 LX42KH, 2018 Ariens Ikon 42, 1961-ish Moto Mower 61-190 18" push mower, Early Snapper V21, 2016/17 Snapper Hi-Vac.
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