Picked this mower up about a year ago - previous owner said it just needed a new drive belt. I had the old one which I took to a store and found it was an M37 v-belt.
Contacted Masport for info on the mower and curiously they claimed they never made such a model (800ST with GXV160 on it) - this was very odd as I have found posts on several sites discussing this exact mower. As the serial number sticker on the mower was missing/unreadable i could not give them this and they said they couldn;'t trace it but felt it must have been a re-engine - but that seems very odd to me and original owner swore it was bought brand new like this.
Anyway.......when i fitted the new belt I found that it did not work correctly. Speed was far too slow - think Grandpas morning walk on a very cold winter day down in Tassy. The handle on the handebars which is meant to control the speed setting (variable you push up or down to adjust the tension on the belt placed by the pulley under the deck) would only go down about 1/2 way - as the pulley was literally against the wall of the deck.
I can't figure out exactly how the pulley and belt should be arranged - this one is pushing the belt outwards, but generally it seems that SP mechanisms push them inwards to increase speed, but can't see how to do this due to it only able to be in once spot.
I have a Google Photos gallery with all the images of the machine and underneath - did a quick MS paint to show where the cable moves to move the pulley but I am sure it's wrong. PHOTO GALLERY OF MOWER
if folks prefer pix put on here instead pls let me know - I've a feeling the belt needs to be fed through the pulley as at present the flat pulley (innermost one) doesn't touch it at all, only the outer (v-pulley) pushes it outwards.
Wow, thats kind of exactly what I suspected the routing might have been but wasn't 100% sure. Makes a lot more sense .
I REALLY appreciate the extra effort you went to with the MS Paint pic etc and I will try and get down to the shed and give a try if this rotten rain clears up.
My sincere thanks for a superb reply, much appreciated.
Ok....I put it on in the fashion shown, wasn't easy at all due to the previous owner having cut or altered the cable that moves the tension pulley.
Alas in doing this adjustment I think I've caused another issue. I had the mower tilted over heavily on its side - not 100% over but well most of the way. I was sure to tilt so the carb was upright and had no fuel in it.
But when I fueled it to try the new belt alignment I got it spluttering to life with a LOT of smoke. No big deal I figured a lil oil went in the cylinder, it'll idle it off.
Restarted and it surges initially and then immediately cuts out.....tried restarting and even with throttle adjustment it quickly cuts out, but not any white smoke anymore. Allowed it to rest overnight, not won't start at all.
Has fresh fuel, checked plug, removed airfilter cover and tried. Nothing seems to work. I've not altered anything else with it so dunno what the possible issue is.
Nick, Did you have it tipped with the carby on the lower side, if so the filter may now have oil in it and if this is the case they won't start. Try starting it with the filter removed. Also pull the plug out and pull the motor over a few times and see if any oil comes out the plug hole.The plug may be soaked with oil, try another plug and make sure you have spark. Then if it still won't start give it a quick squirt of starter fluid in the carby and it should start
Yep what Norm said ,also I would put a rag under the carby and remove the fuel bowl drain plug on the side of the fuel bowl ,let the fuel flow through a little to make sure the fuel bowl is not full of engine oil ,if you can't get to the drain plug, I would first clean around the fuel bowl and carby with a compressor and air gun or just a clean rag that will remove excess dirt so you can then remove the centre bolt from the fuel bowl.
I was very much conscious when I tipped it over to ensure that the carby was always on the topside/upper, as I did know about the potential for oil to go into it. So that shouldn't have been the cause.
The last time I started the mower it went first pull - that was several months ago but as I knew I'd not be using I full drained all the fuel, including via a carb drain and even put a teaspoon of oil in via plug hole.
Anyway to keep simple I will try your suggestions and report back. Much thanks :-)
Ok, this is starting to get somewhat concerning as the engine on this mower always ran very well. I know its best to eliminate the obvious stuff so let me just get those out of the way. - fuel, plenty in it - known good fuel used on other GXV160 engined mower within the past day - cleaned and replaced plug, that didn't work, so replaced with completely new plug, that didn't work - checked and there is a definite spark - emptied carb fuel bowl, made sure all bits in place and clean, no leaks, good seal - used SCA engine starter spray - still reacted exactly the same as without, started strongly but then after ~3sec cut out, adjusting the throttle up or down did not make any difference, no smoke at all - removed the SP drive belt, made no difference - removed the air filter, that made no difference - oil level is correct, only changed a few weeks ago
Kind of out of ideas - never had any issues with starting this one, only SP issues. Pretty stumped so any ideas welcomed. :-/
Dead simple this one, carby is the problem, the fact it will fire on the starter fluid says everything is working correctly except it isn't getting fuel
Yes sounds like a blockage in the carby ,poking some fuse wire up the main jet (centre of carby when you remove the bowl) should clear the jet as long as the needle and seat for the float are working it should run after the main jet is clean.
I figured it was something in the fuel supply area....acting on that idea yesterday I did take a carb cleaner spray with a extended nozzle on it and spray it up there but that didn't assist.
But I will do as you've instructed and try a physical clean instead. Much thanks again. :-)
I usually can't get the main jet out, they are generally corroded too much and often people have used ethanol in them and that is a 100 guarantee to destroy these carbs. New carb tor these are not that expensive and that is what I usually do.
Much thanks for the reply and advice. I'll give it a try and see how I go, worst case scenario as you say I will replace the entire carb. Is odd I've only run the mower perhaps 5mins since I got it, the previous owner didn't strike me as very careful with it - and alas I don't know if I'll even be able to use it properly here on my property anyway such is the luck of 2nd hand buys.
Stumbled across the following document, which seems relevant for this area - hopefully it assists others as these are popular models: Honda GXV160 Carb Troubleshooter pdf
Gee, why would you rebuild when they're that cheap. Much thanks - I'll grab one as handy to have given I'll be hanging onto my HUT216 regardless of how this Masport works out.
