B&S 350 Hard to pull start

[Widget]

[EDITED] Sorry, meant B&S 375. not 350.

Hey guys,

I have a B&S 375 mower which is having an issue with starting. Ill pull the cord and it appears really hard or it gets to a point during the pull where it stops/becomes hard to pull (but not impossible)





story:

- Purchased mower
- Got home, looked at mower, started mower, mower ran (poorly), decides to clean mower (carbs particularly)
- Notices rest of mower is filthy, decides to clean more than just carbs
- I remove base/plate from mower (which has blades attached to it)
- Unbolt engine from base and remove (3x bolts)
- I remove Starter/rewind assembly, fuel tank, carb, Armature-Magneto, muffler (already damaged)
- Drain old oil (through oil input hole, I couldn't open drain plug)
- Clean parts thoroughly
- Re-assemble everything

**2x issues**

1. Won't prime. Bulb tries to suck, put wont squirt into intake, I 'think' it could be an issue with the seat-check-valve(?)
- Removed seat-check-valve little rubber seat inlet thing + bearing + spring. Putting my finger over seta check valve hole in carb Im able to fill the bulb, remove finger and can squirt into intake.

2. Pull starter cord, gets to a point then it becomes hard to pull (put pullable)

- Removed/tested starter/rewind assembly, pulls/retracts ok, can't see any issues there
- Turn flywheel by hand, gets to point and tough to turn.
- Removed spark plug, can pull easy.

From what I can tell, it may have something to do with compression?

I jumped online and read something about Hydro-locked, thought this may be it as I did have the engine on the bench and may have tilted it. I tried starting multiple time with spark plug removed, didnt see any excess oil spray out
- put spark plug back in, still tough to pull start

My mind is totally boggled right now.. I have no idea what's happening Any suggestions ?

p.s. I'm probably not the best at explaining things, but if you guys want me to make a video, I can whip out my phone and shoot a few minutes.

Thanks

 

[Michael72]

Take a deep breath and have a coffee ......if i had these issues (pull cord) I would take cover off and make sure brake is disengaging properly, correct distance from flywheel to coil and no keyway damage....when you had plug out was the movement of the piston smooth?....if you had a hydrolock issue you would have oil spitting out of plug and exhaust...just ignore any other problems for the moment...if theres internal damage it wil lbe a waste of time

Forgot to add...if the vales are sloppy it wouldnt help matters...but check there is no damage to piston or scoring to cylinder.

 

[Widget]

Take a deep breath and have a coffee ......if i had these issues (pull cord) I would take cover off and make sure brake is disengaging properly, correct distance from flywheel to coil and no keyway damage....when you had plug out was the movement of the piston smooth?....if you had a hydrolock issue you would have oil spitting out of plug and exhaust...just ignore any other problems for the moment...if theres internal damage it wil lbe a waste of time

Hey Michael, thanks for the reply

No brake as far as I know. Just put lever to start and pull cord, no handle to squeeze in either.

Distance should be ok. At first I thought maybe Flywheel + Magneto coming in contact, but I separated them both with a business card, tightened the Megneto down then removed card.

What's the "keyway' you speak of? Flywheel key? I googled around and a few people mentioned it being a possibility, might remove flywheel in the morning and have a look.

With the spark plug out and pull starting, it seemed quite smooth, didn't feel much of a resistance, maybe a little, but nothing out of the ordinary I'd think.

With the valve cover off(?) I can see the 2x little valves (with the springs) moving a little back/forth too.


Having the blades/blade base off wouldnt affect starting it in anyway would it ?


Thanks again

 

[Michael72]

No it wouldnt effect starting....if you bring the piston to top dead center then turn flywheel an extra 1/4 inch turn clockwise...at this point you will need both valves closed and then check clearance from the valve stems to push rods (just underneath those springs) .. on that model I think clearence should be .005-.007 on intake and exhaust (the smaller valve) .007-.009

 

[Michael72]

might not be the fix but you might as well have a look since your so far in ....yes flywheel key I should have said!...I would check also that there is no damage to flywheel itself

 

[ILENGINE]

Hey Michael, thanks for the reply

No brake as far as I know. Just put lever to start and pull cord, no handle to squeeze in either.

Distance should be ok. At first I thought maybe Flywheel + Magneto coming in contact, but I separated them both with a business card, tightened the Megneto down then removed card.

What's the "keyway' you speak of? Flywheel key? I googled around and a few people mentioned it being a possibility, might remove flywheel in the morning and have a look.

With the spark plug out and pull starting, it seemed quite smooth, didn't feel much of a resistance, maybe a little, but nothing out of the ordinary I'd think.

With the valve cover off(?) I can see the 2x little valves (with the springs) moving a little back/forth too.


Having the blades/blade base off wouldnt affect starting it in anyway would it ?


Thanks again

The blade acts like a flywheel and while effect turning over of the engine, because you loose the centrifical force. Can cause kickback, loose of cranking momentum.

 

[Michael72]

you learn something new everyday....never had that prob with blade off.. thanks for tip tho

 

[bertsmobile1]

On a VIcta, yes.
You cannot start the engine without the blade disc attached.
No blades fine, no disc = no start and this is worse with the 4 blade disc than the 2 blade disc.

Next check the valve lash good chance they have opened up so the automatic decompression is not working.
You can not pull it over full compression.
Bad news on a sprint engine as you adjust the valve lash by either stoning the end of the valve or cutting the seat deeper both of which require you to remove the head.

I charge $ 60 extra for doing the valves + gaskets ( $ 14.00 Aust ) which brings the repair to close to $ 100 so very few bother as they would rather go to Bunnings & buy a piece of Chineese garbage for $ 150.

If you have access to the gear then go ahead & do it, not a hard job just time consuming.
Replace both the head gasket & the valve chest / breather cover gasket .

If the valve lash is ok then put your finger on the inlet valve stem ( carb removed ).
As you turnover the engine you should feel the inlet open, close then just before TDC open just a touch ( decompression ).
IF it does not do this & the valve lash is within specs then you are most likely looking at a new cam, about $ 70 Aust.
Again an uneconomic repair.

AS it is winter down here, consider buying a new cam from the USA ( Jacks Small engines on the sponsors page ) works out about 1/3rd local price if you get it sent USPS. Takes about 4 -6 weeks this time of year.

Before you spend too much time & money check the deck around the left hand handle attachment.
This is the usuall rust out spot and if it is rusted or cracked there then save your money & get a replacement mower.

 

[bertsmobile1]

OK, just checked out the photos, forget it that deck is toast unless you are thinking about a welding project as well.
You can put your engine on any Victa Deck if you do repair it but that deck is a waste of time.
You can usually pick up a reasonable non runner on evilbay for under $ 10.00 .
Two stroke or 4 stroke does not matter the decks are the same.
Personnally I don't bother with those under powered B & S engines unless you live down south & have fine grass as the low compression Power torque is 5Hp and the high compression one is 6.5Hp
The Sprint is 3.5.

 

[Widget]

Thanks guys,

I'll try take the flywheel off today 1st, see if the key is broken or not.

It's confusing that the issue came up, I didn't really touch anything else, just unbolted a few parts.

if the camshaft was borked, (or other internals) wouldn't you still feel something wrong even with the spark plug out ? (turning flywheel still hard)

Another thing to add, I had the muffler off. As the original muffler was split, I removed it, leaving the opening to the exhaust (where the muffler screw on) exposed. Would that cause any issues? or should the mower still run, even with no muffler attached ?

I originally picked up the mower for $10 (came with a free whipper snipper too). It does have the corner rusted away but the base (and section where rust is) is still sturdy, so not really bothered with a new base. If there is an internal issue, Ill just strip the mower for parts or dump it, though would be nice to figure out what happened with it :/

Thanks again,