# tore apart the 4.5hp, wasnt pretty



## roperdude91 (Nov 10, 2004)

my 4.5hp briggs that i got in april of this year got synthetic oil since new, became near impossible to start cold, and would NOT start after it had been run for any period of time.
checked compression, just shy of 40psi, thats low, so i pulled the head to check the valves, right away i noticed that the cylinder was all scratched up
no peices of sparkplug missing, nothing floating around in the cylinder, nothing fell out when i took the head off, and the airfilter has always been on the engine and clean
i took the blade off, unbolted the engine from the deck, popped the blade adapter off and took the bottom of the engine off
black gooey sludge everywhere!
the oil was changed often, and looked clean when i drained it
took the piston and rod out, piston was scuffed good and the rings were rough.
the crank was scored and the rod was too
WTF HAPPENED? im rebuilding an engine thats less than a year old and i used 10w30 synthetic the whole time not the cheap stuff, the cheapest stuff i used was syntec, and that was 4 bucks a quart and that was only for a a short time, other than that it got mobil 1 10w30
ive got a '78 3hp that still has the cross hatch marks on the cylinder, and 3.5hp motors that barely have any wear
the van's cylinders look better than the 4.5hp did :freak: and that motor wasnt taken care of until earlier this year
they were so good i didnt bother honing them when i had the engineout and in peices everywhere, i just replaced bearings, rings, and gaskets(i really should have done the valve guides, the 3.0l chryslers were known for bad ones, and due to that mistake, it still smokes on cold startup and at idle for a couple of minutes) atleast its not as bad as before lol


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## bugman (Aug 12, 2004)

thats kinda wierd indeed.... i use the 10w-30, if i can find it, going to use the 5w-40 mobil one. no problems to speak of after one season... about how often was the oil changed? lots of other people i'm sure use 10w-30 mobil one, and their engines are getting of age. also any pictures of the damage could help... its also a possibility, (foam filter?) that it maybe had a hole or leak somewhere.


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## roperdude91 (Nov 10, 2004)

changed the oil once a month and the filter didnt have any holes in it and it fit snugly in the housing, i see no way of it leaking, i was using an older style metal housing and filter with the lip on the foam to form a gasket between the two halves of the housing


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## bugman (Aug 12, 2004)

what about the gasket between the carb and filter box? you were using the older style filter box and filter.....the one without the point on it? also on the oil part, theres people using 5w-30, 0w-30 in them.... i don't think its a oil problem, mobil one is thinner, but would flow alot better past the rings and such. about how much sludge?


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## bbnissan (Nov 7, 2004)

It sounds to me like you ran it really low on oil at some point. I've seen engines that have ran on everything from 20w-50 regular motor oil to 0w-30 synthetic oil and I have never heard of one doing what yours did unless it was really low on oil.


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## roperdude91 (Nov 10, 2004)

was never more than 1/8 of an inch below the full mark, i checked the oil before i started it every time, and if it was even just a hair low, i would top it off


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## bugman (Aug 12, 2004)

any steep slopes maybe?


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## roperdude91 (Nov 10, 2004)

nope, it was used for trimming around stuff in peoples yards


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## Phil F (Feb 16, 2005)

did you use regular oil for the breakin of new engine then use synthetic afterwards


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## Scott15 (Nov 11, 2004)

They don't make em like they used to.


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## roperdude91 (Nov 10, 2004)

Phil F said:


> did you use regular oil for the breakin of new engine then use synthetic afterwards


for about 5 hours


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## bugman (Aug 12, 2004)

would've allowed more of a break in on conventional, once for the 5 hours, then 25 hours or a little longer, then syn.


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## bugman (Aug 12, 2004)

Scott15 said:


> They don't make em like they used to.


 nope, sure don't, they are either made the same, or better, of course every manufacturer has a dud.....


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