OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Honda Engines honda power!...not

hi chaps,
haven't stuck my head in the door for a long while namely due to being carried away into the world of computers and auto mechanics.....how miserable! i must admit i actually miss reading the posts on this forum and generally helping people out.

so anyway i found a victa utility with a honda engine on it in rubbish collection.
got it home and it wont suck fuel through the carby and when you stick some down the spark plug hole it pops back out the inlet manifold. valves are sealing correctly (not like old brigges that throw valve seats without rime or reason). i checked flywheel key...fine so im thinking maybe the timing belt skipped a tooth or two. haven't got the crankcase open yet because the boss wouldn't come off and i dont want to cut it because i dont have any others for victas.

i hope i haven't missed anything stupid. but it has decent compression ect so its worth the effort i think.

thanks
regards jay

mowernut,

The bet is that the timing belt has jumped a couple of teeth throwing the timing out.

If it blows anything out from the cylinder to the intake pipe, it sounds like the camshaft timing is wrong or the intake valve is stuck. If the compression is good, camshaft timing seems the most likely problem. Probably the intake valve is staying open during the early part of the compression stroke, due to late valve timing. (When the timing jumps, usually the crankshaft finishes up ahead of the camshaft). If the timing has jumped, you have a loose belt - don't just re-time it and restart it.

I once had the timing chain jump on a car (a ludicrously worn-out ex-cab), right at the point when we set out on a drive from Perth to Melbourne. The car would then only go 35 mph, so we stopped in Kalgoorlie and took a look. By then the exhaust valves were small and square, and a couple of the valve seat inserts had fallen out. Continuing to Kalgoorlie was not a good decision. (With old car engines the camshaft drives the distributor, so it had very late ignition timing when the roller chain jumped on the sprocket. That was the main cause of the low power and high combustion chamber temperatures.)

thanks bruce and grumpy.
the first thing i suspected was the timing belt because the flywheel key and such was in good condition.
Ive got it apart now and cant find any timing marks on the crankshaft so i assume you set it at top dead center and like the cam marks with the top of the block.
As to timing chains i drive a 2.6L Mitsubishi Magna...about the worst chain tensioner system known to man. the counterbalance drive chain has jumped in the past and it vibrates like hell because the shafts are then out of sync. not a good thing considering the whole engine has to come out to replace the chain and sprockets.
thanks for the help
regards jay

Here is a posted description of how to set the belt timing:
http://en.allexperts.com/q/Small-Engines-Lawn-1746/2009/2/set-timing-GCV-160.htm

The GSV190A manual says "Set the piston at top dead center of the compression stroke (both valves fully closed). Top dead center of the compression stroke is in the position where the cylinder head cover mating surface is in line with the cam pulley alignment marks." This seems to be the same thing the website says. Two references that agree, and one of them is the designer of the engine, sounds like pretty good evidence that is how you verify or set the timing. Furthermore, that sounds fairly much like what you intended to do anyway, but it is the top of the cylinder head, not the block.


Please let us know what you find when you make that check.

im now away on holidays over Christmas but when i return ill have a look at it.
i did roughly place it all together last night and turned it over and it seemed to be good. the only thing is that top dead center is a bit of a touch and go proposition because the belt only lines up just under or just over top dead center. i suppose its better to be slightly advanced.

thanks for all your help
regards jay

It's best to find TDC by looking at the keyway on the front of the crankshaft, and getting it vertical. You can do this pretty accurately. If you can't get it to line up properly, something is wrong - you might need to check that both of the pulleys are tight on their keys. If it isn't that, there might be wear on the belt-teeth.

the crank pulley seems to be pressed onto the shaft because i cant find any way to remove it. ide say its more wear in the big end of the con rod causing the piston to slip just over center. but i have a very crude way of taking slop out .
the belt is probably a bit flogged but ill just wack it together and not worry about it if it runs. ide say the belt is probably a bit stretched too.
it also doesn't help that i couldn't actually see what i was doing on the dark last night!
thanks for the help once again.
best wishes for Christmas and the new year
regards jay