OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Is this engine suitable for Rover 45 reel mower?

Hi, I finally managed to be a proud owner of the used the Rover 45 reel mower, after so many years of drooling over the next door neighbour's one.

I am wondering if this Briggs and Stratton OHV design 163cc Cast Iron Sleeve and ball bearing crank standard, model no 106232 with standard with 3/4" shaft would be a suitable replacement for the B&S 3.5 HP 91202 engine the Rover currently has.

Thank you with kind regards,

Hien.

Hi Hien Do, and a warm welcome to the forum. Its always nice to welcome another Rover 45 owner on board.
I am sure our resident Briggs and Stratton guru grumpy will chime in here and give you the correct advice on the engine replacement.
Once again, to Outdoorking.

Under the old rating system which credited your 91202 engine with 3.5 horsepower, the 106232 would be rated at about 6 horsepower. This is due to its larger capacity, higher compression ratio and OHV design. (In reality both engines have far less power than that as-installed on a mower, but it gives a realistic idea of one versus the other.) I regard it as a somewhat oversized, overpowered engine for your SB45. If it conforms to the standard small-engine mounting dimensions, which Briggs engines normally do, it should fit fairly easily onto your mower as a direct replacement for the 91202. Aside from being rather larger than necessary and an Intek engine, it seems to have a good specification, and would probably do your job quite well. I generally lack enthusiasm for Intek engines, because of what I see as significant design errors made in the larger ones, but those issues do not apply to the 750 series. Also, the 750 is likely to be substantially smoother-running and more fuel-efficient than your 91202.

I personally regard the Honda GX120 as both a better engine, and a more suitably sized one, for the SB45 compared with the Briggs 750. However as some American said many years ago, "Opinions are like backsides: everybody has one." I do not know your reason for choosing such a large engine (160 cc and 6 hp, versus the Honda's 120 cc and 4 hp), and it may be a very good reason for all I know. In general Briggs engines cost less than Hondas, and as the world's largest manufacturer of small engines, Briggs obviously must be doing something right.

The usual crankshaft extension diameter for the GX120 is 3/4", the same as the 91202. Note also that matching engine-side clutch-halves of both 5/8" and 3/4" for the SB45 are available as spare parts.

Thank you, Deejay. First post, but has been reading the posts and watching the videos of this great site for months.

Dear grumpy,

That is TOP advice.

I shall search for a Honda GX160 as I originally planned to do.

The reason for the new engine is just for the new engine. And I shall play around with the older BS as a learning curve.

Thank you so much with kind regards,

Hien.

Hien, I do not regard the GX160 as being a particularly good engine, or a particularly suitable one. It is as big as the Briggs 750, and was the "stretched" version of the GX120 family, resulting in a bit less efficiency and and perhaps somewhat less pleasing operation. That does not make it a bad engine, but one that is probably not much more suitable than the Briggs 750. The GX120 is the right size for the job, and was probably the nicest member of that engine family. I believe some other Outdoorking members have fitted GX120s to SB45 mowers, and seem pleased with them. I use a GXV120 (the vertical version, on a Honda rotary mower) for my regular home lawnmowing, and regard it as excellent.

The Briggs 91202 is a decent engine, in its time one of the very best. You should be able to have some fun with it, and learn a lot without much concern about making an occasional mistake.

More food for thought, Grumpy.

Much appreciated.

Hello Grumpy,

Can't afford Honda engines.

What do you think about Briggs & Stratton 3.5HP (550 Series) Petrol Engine? And, having watched your instructional videos, anything I need to be careful of when replacing the engine.

Thank you with kind regards,

Hien.

Hi Hien, I can well understand you not wanting to pay the price of a new Honda engine - I've only bought second hand ones myself.

The Briggs 550 series are entry-level engines with aluminium cylinder bores. This means that they are capable of lasting a long time in home service provided you change the oil regularly and keep it topped up between changes, but they are not suited to commercial uses. The horizontal crankshaft engine is 127 cc OHV, which is well suited to your needs. (The vertical crankshaft version is 158 cc OHV.) Note however that the standard output shaft (which Briggs calls the PTO, or Power Take Off) is 5/8". You have said that the current side valve engine has a 3/4" PTO, so you would have to buy a new engine-side clutch half for $80. This is quite significant in proportion to the cost of the engine, which is $220 in the US. On the other hand, if your SB45 turns out to have the old captive cotter style of engine-side clutch half, there is a possibility it needs to be replaced anyway.

You have not posted pictures of your SB45. There are several things that might be wrong with it in addition to the possibility of wear/damage to the engine-side clutch half. I suggest you post a series of pictures including showing the engine mounting area, the cylinder reel, and the chains & sprockets inside the chain case on the left side of the mower. Deejay, our reel mower guy and the star of the Outdoorking videos on repairing SB45s, can then discuss it with you.

Many thanks for the advice, grumpy. I shall take and post the photos sometime this evening after work. Cheers, Hien.

Hi Hien Do, once I see the pics I will be able to give you advice. Looking forward to seeing them.