OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Briggs series 450

I have a mates daughters here at the moment, it is a Series 450 Briggs on a Sprinter base. It had bits missing from it, it came from her father in law, so I'm guessing he had had a fiddle with it. It had no spark so I replaced the coil and got it up and running fine. Yesterday I started it again to show my mate and it is now hunting on the governor, no probs I thought, just swap a known good carby/tank onto it and all will be good. Not to be, still hunting exactly the same as the original carby. Any thoughts?

Well NormK you should by now hopefully know we the model and type numbers of the engine so we can get on the same page. I learned not to guess at things as these could either an air vane governor or a mechanical version. It is because I don't see many push mower any more as the repair costs are nearly the same as a new mower around here.

If a mechanical governor it may simply be out adjustment and a static adjustment may resolve the problem.

Hi AVB, I know about these model numbers but they are usually too hard to read. It hasn't done a lot of work these little 16 inch mowers never seem to do that much going but external appearances. It is a vane type and everything appears to be functioning as it should. I usually find that this problem is in the carby and with a few revs and hand over the carby they usually clear and settle down. This one didn't so I fitted another tank and carby but that made no difference

Okay take a good look at the intake crossover tube. I have seen a few with holes in the under side of them causing an air leak (ie lean burn issue). Kinda stupid on Briggs part for using plastic instead of metal. Also don't forget about the o-ring seal. From there I nearly need it in my shop to figure it out but you know that is impossible.

Thanks AVB, I think you could be on the money, I have found a few with holes in the tube, worn around the "O" ring. Guess I should have looked closer at those bits but this mower appears to have done very little work, it hasn't been cleaned up and still looks in excellent condition. Problem is as you say they really are not worth the time/effort because replacements are cheap. I also fixed up for my mate a Victa 2 stroke utility/slash, probably late seventies early eighties which he had brought here for me to get running so he could use it in his mowing business. By the time I repaired the axles,base,new rings,modified the carby, changed the blades and blade carrier and got the thing running as it should, I had spent about 8 hours on it. I charged him $40 for the parts I used. I told my wife yesterday that I will set myself a challenge to fix at least one mower a week for the next 12 months and that should make a big impact on the pile of mowers I have here, as long as I don't get any more!!

I just got another email from my mate, he is so stoked with his utility/sidethrow Victa, He rang me this morning after he had given it a try out and now he has emailed me about it. It is not like I restored it, it is a rusty, probably a min of 35 years old mower that has years of life left in it

G'day NormK,
it's nice to see a Victa rescued from the junk pile going appreciated. It will be his go to mower for the tough stuff. I had a side pull full crank utility that sat exposed to wind and rain (when blown in) unused for 4 years and it fired right up, albeit smokey. The height adjuster froze but some well placed WD40 had it moving up and down freely within a week. it was so nimble and light, compared to a regular domestic catcher model and I used it to tackle some 2 foot growth at the rear of my yard that had been left unmowed for years, due to obtacles everywhere. I wished I had done it sooner as it made the area look like it had been professionally landscaped!
Wishing so hard I didn't give it away to a neighbour for spare parts. hopefully he hasn't parted it out.

Hi AVB, I got to have another look at this motor today and still no joy with it. Manifold tube is fine and sealed back onto the head, replaced the "O" ring fitted a third known working carby and it still does exactly the same. I'm wondering if a head gasket may be the cause but as it is a freebie job I'm loosing interest quickly

Ok so I just worked out a fix/bodge to get this motor to idle without hunting. I riveted a small piece of sheetmetal to the cowl to prevent the vane from completely closing the carby butterfly, and this being with one rivet, I can adjust it to get the revs to settle in a manner similar to adjusting an idle screw. Works fine now so I will do it to another one that was giving the same problem.