OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines hard starting 5HP

I bought a 5Hp Rover Shredder with a blown motor. Rod through crankcase job.


I bought a Rover super four 21" with a white 5Hp on it that i bought for its motor.
Had a fiddle with it last night. 80psi compression, and a good spark. 5 thou inlet, 8 thou exhaust so thats all good. Fresh fuel in the tank, no go.
Fuel down the carb and it goes but wont keep running. Put the tank off the Shredders blown motor on it, got it set up, it will run and got it tuned OK, seems a bit rich but still gives a lean cough when winding the mixture screw in. Back it out a bit and when you rev it it still pumps a bit of soot. Not to fussed about that as its not under load.

Shut it down, and it wont start hot. First compression stroke of the first pull it fires once but then nothing. Put it on choke and it will fire a few times and you have to be quick but if you can flip it back to a slow engine speed it will catch on.


Any ideas???
Could it be spark?? should i put the electronic coil on it off the blown motor??? Perhaps its a bit worn or the timing/points are not set up right.

Open to suggestons.


Ive got a rover side throw as well, its got a 5hp I/C motor on it. Going to look at it tomorrow. I might use it instead. The Shredder is a keeper.


Bob.

Bob, it sounds like a reasonable fit for a deteriorated fuel pump diaphragm. You might try changing over the entire fuel tank and carburetor from the other engine, without separating them. If it works, it is most likely a diaphragm or carburetor fault in the current tank and carb. I think your odd symptoms could be due to a combination of poor fuel pump and carburetor tuned rich to compensate.

Thanks Grumpy.

I did the tank swap.
Then i was thinking whats the chances of both diaphragms being past it.

I think what i might do is the the digaphram and do one carb. Then i can use that one tank on both motors, the white one goes OK, 80psi is pretty good compression. Will work it out after i have looked at the 5hp i/c today to see whats up with it. With the iron bore and perhaps with fresh rings theres probably a good chance it will use less than a sump full of oil to a tank of fuel.

The Shredder i bought for the old boy, its looking like it would do about 5 tanks of fuel to the sumpfull. And i bought it off an old guy that bought it new and it hadnt dont that much work.

Id say the blown up one i bought got to the tank to a sumpfull stage. It looks like its done a power of work. They have a pretty big fuel tank on them.




Cheers, Bob.

Did you try it without the air cleaner? A dirty air cleaner could make it rich at high speed and lean at low speed.

If it isn't the air cleaner, and you clean the carburetor and replace the diaphragm and it still doesn't work, it would be time to work through the problem step by step from basics.

I'll keep the thread open Bob - please keep us posted.

Had a bit of a play about this morning.

The white motor i had running yesterday, I havent touched it again yet.
I was running it with the air cleaner off. Generally do that to all the 4 strokes. Then fit one and retune and test it.

Its got all the stuff off this motor on it.


Dragged the super 4 into the shed and had a look at it. Got good spark and no compression. Well i didnt test it, it feels like it has none. No clearnace on the inlet valve. Inside the fuel tank looks bad.




Dont mind the mess.

So i stipped down the blown red motor, spare valves and head, the one on the I/C motor has the front cover bolt snapped off in the head.

Went off and bought 2 new diaphragms $6.60 for the pair.
The tank and carb i took off the white motor i stripped down.
The pickup tube was blocked up. Sorted that, stripped the carb down and clened it all out, new diaphragm and its ready to go back on the tank.
The inside of the tank was dry but absolute filth. Went out in the yard and got a collection of stones, loaded the tank up with carby clean and spent the day giving it a shake every so often while i sorted out a couple of power torques.



Tiped the stones and carb clean out. Dosed it up with some heavy duty degreaser. Rinsed it out in the laundry trough and then put it in the oven @ 250F to bake.


Its back out in the shed now. Not sure if ive stuffed it, shouldnt it wasnt hot enough to burn the paint and i left the door open a bit, it looks like its had seam sealer along the join and some of that has come away. Wait and see tomorrow when i fill it up if it actually needed the sealer.



I wanted to get these 5HP's sorted and out of the way. Ive got some 5hp quantums here off rusty MTD bases and they need homes. Not real sellable on the old bases, but the bases would sure outlast the motors.

Will pull that black tank off the white motor tomorrow and give the carb a clean out and a new diaphragm. Could be that its a bit stiff and hard and not pulling fuel up like it should making it hard to start. Or a partly blocked hole or something.
Hoping to put the I/C motor on the Shredder. Keep the other one for one of the 18" side discharge mowers i have here (got a galvanised Vulcan) to leave at my Grandmothers, or put it on a Big Bob.


Whats your thoughts when converting to electronic coil?? Leave the points etc in there, or remove it???

And another question. The Super 4 has the vee belt pulley on it for selp propell, how hard is that going to be to get off the shaft???


Bob.

Hi Bob, since your white engine had its carburetor fuel intake clogged up, it sounds like you are doing some good, even if it turns out not to be the diaphragm. Generally similar symptoms, probably.

Joe Carroll has converted a few B&S breaker-point engines to Magnatron, and posted about it on this site. You don't need to do anything with the points except disconnect the wire - they can sit there and open and close if they want to, nobody cares. I think I'd leave them there at least until you had thoroughly tested it with electronic ignition, so you are keeping your options open.

I don't know anything about the self-propel mechanism. We either need pictures, or for someone who is already familiar with it to join in here.

I just took the pulley off a self propelled super 21 like that, after 35 years it was rusted solid on there and the only way to rewmove it was to cut it off in that instance.

Be gentle with the fuel tanks, I have several leaky ones and no good ones at all, one cracked around the welds that hold the mounting bracket on, one was weeping around the edges and the other had an obscure leak I cannot recall.

No need to remove the points, maybe if you were fitting it to a kart or something and wanted to go extreme on weight reduction it would matter otherwise they will just sit there and not affect the engines running.

skip the first minute and you will see in part of this vid how to replace the points ignition.

Thanks for the Vid Joe.

Thats what i had planned on doing, something along those lines.
I did the coil swap/conversion on one the other day.

Only one question, i have a mower here that i bought off a guy and it looks like someone has done the primer carb swap, they dont have a mixture screw, how are you meant to tune it. It sounds like its running lean.
The motor is worn and he said it was getting low on comp so he pulled the had off and took it too work and skimmed 1mm off it.



Back to the 5Hp.


Does anyone have a 5HP conrod for the I/C motor???

Pulled the head off to sort the valves and you spin the crank and the piston stays still. Bit bummed out about that.



Put the cleaned out and kitted carb and tank back on the white motor and it started up straight away and runs pretty sweet.

But, the carb is leaking. I am hoping its from the gasket between the carb and the tank. I re-used the old one. Should i just cut a new one out of gasket paper and fit it dry?? Or put some non setting permatex on the old one?? Or get the genuine part??




I bought some bits and engines off a guy ages back. Was supposed to be 3 sets of Victa rings in the lot of stuff. Can anyone tell me fro the markings what 5Hp and 3.5Hp motors these fit???







More to come later on the I/C motor. Need to split the casings and see if its worth chasing up a conrod and buying a gasket or two.

Not having much luck, found that yesteday in the I/C motor then the pissed about forever fixing up a Masport steel base/frame and the 5Hp Quantum i grabbed to put on it was stuffed. Run low on oil and the top bushing has grabbed the crank and its stiff to turn.


Thats about it for now.

Bob.

Oh, i did try getting the boss off the crank. The big fat one for the blade, No joy, going to have to surgically remove it.

I don't recognise that carburetor on your white 5 hp Bob. Is the gasket between the carburetor and tank actually a fuel pump diaphragm, like on the pulsajet? If it is, you will need a new one, and no messing about with gasket goo. If it's just a simple gasket like on the vacujet, I tend to put them back on with a bit of non-hardening goo if they are only moderately trashed (no breaks anywhere, just some surface roughness). However I'm a notorious cheapskate. If you goo them, you'll destroy them next time you take them off, so it's only a temporary solution.

That carb is the same as the one on the black motor.
Not that different to the one thats on the I/C motor.

Its only got the small diaphragm under that side pannel.



I might have a go at gooing it up.
If all else fails ive got the part number. lol.

I was thinking of going past the Mower place down in Altona North this morning. They have lots of random gaskets etc, thats from kits that have been split up and stuff thats been jumbled about etc.




Bob.

If you use a new thin cardboard gasket and put it on clean dry surfaces, with maybe a little engine oil on the gasket itself, in my experience you can usually dismantle and reassemble it repeatedly without damaging it. However any trace of other substances on the surfaces and the gasket splits (delaminates) when you take it apart. Of course it depends on the quality of the cardboard.

I have a roll of propper gasket paper here.
The old one looked OK. It busted through the screw hole, left front looking at it in the picture above. Think i will just try cutting a new gasket.

Have not got back to it yet. Not sure what i am doing, may have to use that white motor in place of the I/C for the time being. Bruce has the rod in the shop for $40 or so which is not bad, but then i will want to order up other stuff and i spend all my hard earned on dead mowers over the weekend. More to come on that, there will be a few threads popping up.


Ive spent a bit of time on the 5Hp OHV, just need to get some new fuel line and it should be done. Its going on the Supercut 260 frame and the 260 motor is going on the side throw super 4 that the I/C motor came off. I think the 260 is a 4HP i/c motor, have a nicer looking red lid for it that i found in a stash of parts.

Mainly been busy fixing Victas. Did a few 2 strokes and ive got a big line up of Tecumseh's that ive just started on.