H 16hp Bolens

[davidbliss]

This shows after getting on for thirty years the condition of the deck but still needs looking after as even the one thats just been galvanised I have just spayed with rust preventive as it clings on where it doesn’t get much impact from the grass.

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[davidbliss]

Like every thing thought it was ok, however the side shoot with my mod to hold it up out of the way, now being under tension for a while it warped so has had a bit of tensile stainless put across, so now its fixed?. photo of the early alloy that I modified 40 years ago and the later poor plastic spent more time flapping now works.

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[davidbliss]

I now have mowed my grass twice (nearly two acres) although was dry the grass is still very mushy and turns into a sticky green mess, however scrapped the thick lumps off and left the thin coating on to dry, this I gave another coating of rust preventive as if left long enough will dry to a very sticky coating and as it wicks into the grass coated parts adds to the protection.and mostly when cleaned before winter the less high impacted area’s still show they were still protected like you can see on the first deck had galvanised.

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[davidbliss]

Are there any electronically minded wizards out there, as would just like to know why this happened when replacing a single cylinder engine with a twin cylinder that uses two ignition units, as most people know to stop an engine with magneto ignition it is just grounded to earth. Now doing my engine swap all the original wiring for alternator and ignition were the same fittings as same make of engine, I was very pleased with how easy my conversion went, connected every thing up turned the key and engine started and so pleased just how silent and smooth, must fit the deck and give it a go, and went to stop it, funny it kept running but sort of lumpy at idle, opened the throttle and ran rougher than ever, so easy to short the ignition with a screwdriver, there are few wires to trace on the ignition switch, live feed, one to deck clutch switch, one to alternator and one to starter solenoid, no earth so what happens, ignition off and it was connected to the starter solenoid how very odd, so had to fit a relay that was simple, Its a good job I did as friend was trying to find what had gone wrong with his ignition switch and fed live down the stop wire that blew both ignition units, very expensive and had to take the engine out to remove the cowling to gain access, Photos A must fit is a 15 amp fuse unit top left,the by-metal overload is not fail safe, if fuse blows with relay engine stops, as had a voltage control fail dead short, note lifted so air is blown under, new ignition switch centre, relays bottom right.

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[wristpin]

Reading the above I have to admit to loosing the plot a bit. The OP would seem to know what he’s talking about but it’s as well to understand a few basics.You don’t actually mention the brands of engine , so I’m assuming Briggs.
The ignition is entirely self contained and does not require any external power ( the OP already touches on this and its expensive consequences) The only connection between the ignition coils and the ignition switch is one terminal that grounds it when the switch is off. Buried in one of the Briggs manuals is an instruction to perform 50+ on and off checks that said kill terminal never becomes live due to an internal fault.
In addition to the kill wire from the coils to the kill terminal of the switch , there may also be a diode harness connecting the two coils which stops them interfering with one another . Failure or absence of this harness can produce some strange consequence, such as running on one cylinder or continue to run on one or with the key in the off position. Again, buried in one of the manuals is a little chart giving the various combinations of symptoms from diode failures .
For what it’s worth at this stage, my best advice is – disconnect the kill wire from the coils and add your own kill wire, which by grounding, will be your only way of stopping the engine . Check out the diode harness and renew if faulty . Then fire up the engine and check that it runs on both cylinders and stops on both when your kill wire is grounded. If it performs correctly you then know that the ignition is ok.
Now don’t reconnect the original kill wire until you have ascertained that none of the alterations, additional relays etc, are introducing a spurious power feed to the ignition kill circuit.
Then with the aid of a wiring diagram, Check out the charging circuit. Note that the square box with the yellow wires is the rectifier regulator and needs 9 volts to operate . If there’s a flat battery and the machine is jump started , the machine will never charge. Start with a fully charged battery. Also note that the rectifier regulators are specific to the alternator type and capacity. Again, there are charts showing the various options of alternators and their appropriate rectifier regulators.

• This reply was modified 1 year ago by wristpin.

[davidbliss]

I went down the safe route and fitted the relays, as done same conversion before, there were two single cylindered engines, one Tecumseh and Briggs, both with same wiring set up, when the twin cylindered Briggs engine was fitted, it effected both ignition units, I was just curious and like to know why so know what not to connect to cause a expensive mistake, I ran an early car for some years using its original trembler coil, had done just under a thousand miles and decided for reliability to fit a modern made replacement with superior insulation and components?, within only a short while the timing wiper had arced, scored and then sort of filed its way into the original 100 year old rotor nearly destroying it, against the purists made up a electronic switching unit, so the original wiper done the ignition timing and the electronic unit controlled the trembler, without thinking while testing my setup was using a small battery charger instead of a battery, ok on the circuit but put it direct on trembler, what ever it back fed it instantly blew the two diode’s in the charger, on the photo I posted on side of the starter solenoid they fitted a condenser? or something for a reason as never seen any other solenoid with anything. I still have a few trembler coils ideal for testing spark plugs for insolation leaks.

[richard-hawes]

Do you still have the Briggs opposed twin. I have a Bolens Hydro 16 and the engine has just given up the ghost.

look forward to hearing from you

Regards

Richard

[davidbliss]

Sorry all parts have gone.

[richard-hawes]

Thats a shame, but thanks. Does anyone no of another Briggs opposed twin Horizontel shaft engine thats available

thanks

[davidbliss]

I now have re-engined two Bolens with a V twin, because of the V configuration no need for the UJ joints that fail only need just flexi-joint couplings as it sits down in the frames lower with a strait drive line and won’t knockout the hydro charge pump bearings. First re-engine one I done was 22 years ago and still runs as good today, its a made in Japan Briggs 16HP and seems to run on fumes and was far more economical than the single cylinder Tecumseh it replaced, now the one have just fitted is a US made 18HP and is terribly juice hungry and unless its run flat out soots the left cylinders plug, infact it runs weak flat out at 3600rpm thats uncomfortable at that speed but at a comfortable speed runs very rich, it starts from cold without choke, it has no adjustment for slow running like the old one that idles very slow and silent, so if you can get hold of an early Japan made one that seems better better built, as we had little grass because of the drought last year I never drained the engine oil last year so now will be the third season and is as clean like been done yesterday, now the new one within a few hours had gone very black and already been drained and will see how fast it changes colour, both are running on same E5 petrol so should behave the same. Talking to Briggs is a waist of time just saying contact your suppler,

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[andyfrost]

Regarding the rich issue , did you get any handbooks with it that explain different fuel jets for varying conditions. The reason I ask is I’ve just had similar issues with a very early Honda engine , changing the main jet from 85 down to 80 has cured the problem.

Andy.

[davidbliss]

The only thing that came with the engine was a few sheets with assembly diagrams for conversion to add dual drive shaft drive and oil filter adaptor with torque setting for the set screws, absolutely nothing on service intervals, I think the jets are just pressed in will have a look if I get time or end of season, its a easy carburettor to get the top off but to get the hole unit off the engine has to come out from the frame, them cowl off just to gain access to only one inaccessible screw. Its very noticeable mixture is weak at at high revs as going from forward to reverse the governors snatch full open momentary, where the other engine you cant even tell that you’ve changed direction.

[andyfrost]

My problem was just the opposite , it was running too rich , I toyed with the float level for ages , then downsized the jet and it now runs like a clock.
Does yours improve with a little choke applied.

Andy.

[davidbliss]

I did try a bit of choke and it does stop the hunting, I would rather it was running weak at the lower rev range as it would keep the temperature up but at the moment running it fast to keep the plug clean it gets very hot, so have to let it idle some while or it sounds like a bird scarer a few seconds after turning it off, then at the lower speed end being rich can’t be doing that left cylinder much good running rich at a nice sensible speed.I did take the top off the carb but never went any further, I was wondering if I could drop the float level but its got a plastic float, if it had a brass one could have bent its arm.I did ask if I could get one of the old carbs like off the japan made engine, but they said the manifolds are different so might not fit and with it being £5 short of £200 wouldn’t be to good if it didn’t fit.

[davidbliss]

Andy
Was going to leave it till winter but is so annoying it starts rich without choke and can snatch the throttle open and it instantly picks up without hesitation, whereas the other engine will just stop and once its been run a short while is fine, this morning I started it and seamed worse for a time so took the top off and had a good look and the two visible jets have slots in for a screwdriver so they are removable. I will try the agent again and se if Briggs suggest a smaller slow running jet or bigger air bypass, could only see these two jets, however can see plugged porting, I have had carbs before plugged like that but the plugs could be removed to adjust.

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