I hope to list the various probs that arent covered by the manuals here

PHOTOS FROM VIRE 6 BVR

SPARK PLUG PROBLEMS

fit a new Champion L86c plug every year, (champion L-8/L-10 equiv), this should solve almost everyone's breakdowns,

My experience, is NEVER fit NGK, Bosch etc if it is possible to source Champion - although the spark seems bright, the champions seem much better at cold starting and last years not months!

I saw this at gosport, we fittes a brand new BP6HS out of the box, and ran the engine for 1 minute, removed the plug - very oily(20:1 oil).

HOW TO CHECK TIMING

remove plug

get crank to TDC(within 2mm), by feeling piston thru plug hole with screwdriver as you turn flywheel

mark/paint flywheel 'T' at exact top - (where dynastart bracket bolt is)

measure 2 inches along pulley circumference to the right (looking from front), mark/paint 'F'

replace plug

attach an automotive timing light (borrowed from mechanic?) to the 12v/earth/HT making sure any advance-knob is set to zero

run engine - any speed will do

point strobe light at top of flywheel and note 'F' mark should be at top

if 'F' mark is to the right, the timing is advanced, if to the left, too retarded. (2" is 30 degrees).

Alternative: - connect continuity tester/ohmmeter between engine earth and kill wire (points) with kill switch off(run), rotate flywheel past TDC/F, note the resistance changes at exactly the firing point - much easier than using a lamp/strobe etc.

qnother method, is to place the spark plug electrode over your marks, and they light up like a strobe if you are in shade.

HOW TO ADJUST TIMING

note first you should have points gap correct 17 thou?? assuming that.....

remove flywheel cover, not flywheel!

slacken the 3 magneto base plate screws

nudge the base plate clockwise to retard the ignition, anti-clockwise to advance it (by the same angle the timing was incorrect)

re-tighten screws

replace cover

re-check

ENGINE DIES

if the carb is backfiring a cloud of smoke, most likely problem is poor plug and if a new one doesnt cure it, you might try a new or exchange carburettor which will be overhauled with new diagprams and fully tested(contact me for this unique service). Possibly if the backfire sounds like a bellows going, and the smoke fills the engine bay it could be that the exhaust pipe is collapsing - if the water stopped flowing into it, the flexible exhaust hose wont last long! Certainly if you are lacking acceleration and power is down below 5 knots/difficult starting, and the carb has not been rebuilt in the last 5 years it will be worth eliminating with a fully tested unit.

ENGINE FADES

if the power is hesitant - overhaul/replace carb as the galleries may get blocked or diapragms stiffen inside. Also check fuel system is free flowing, and has inline grit filter & water trap.

A cylinder head that is too hot to palm is overheating, and it could be either impellor failure or corroded/silted water jacket/exhaust which will need backflushing/poking with coat hanger thru holes etc.

PLUG FOULS

Champion L86c @ 20 thou? if not that is likely problem. Timing ok, carb overhaul needed, or fuel has too much oil (modern 2T oils can mix @ 50:1 vire 7) possibly bad fuel if unfiltered carb problems common,

make sure plug has correct gap and type, renew regularly and always carry a spare in good cond with a plug spanner hung up NEXT TO the engine for emergencies

RUMBLING/VIBRATION & slight play in pulley

main bearings have rusted - remove and rebuild asap preferably with stainless set which i supply

KNOCKING VIBRATION

ignition over advanced - check point gap 17thou and timing2.25" btdc flywheel circumference(30 deg) properly

SUCKING sound / poor starting

possibly carb air filter has fallen out

SQUEALING fan belt/no flywheel movement on starting

loose belt?

if the pulley wont go round freely it could be partial engine seizure due to main bearings / piston corrosion  - probably not winterised caused problem.

NO CHARGE from dynastart

battery should have over 13.5 volts at any medium revs, so if the volts dont go up when the engine runs - look at the wiring - is it secured? check the output terminal on the regulator, and if suspect - i supply exchange/new units -

Disconnect D+ and DF terminals(8mm taking care not to swivel corroded bases), earth DF, on medium revs and the D+ voltage should rise to above 15V or the dynastart is caput - probably failed coils, corroded shorts or occasionaly brushes. I supply replacements/exchange units.

Reconnect DF, D+ to regulator, now measure voltage earth to D+ at medium revs. if it wont go above 13.5v the regulator is clapped - probably dirty contacts which are nearly impossible to clean, or a blown fusible link. Replacements available from me.

Dynastart-new bosch units are avail at about £600! I can souce new Vire Dynastarts much cheaper, and have an exchange for less than £200. commonly the field coils go so you will be able to start but not charge! if this is so, you could always save money by adding an automotive alternator with some bracketry and longer belt?

Bosch regulators have a fusible link inside that blows if wires become loose to the battery, this is easy to resolder the open circuit wire in situ (se electrical page)

The reason the dynastart coils go is because on the Vire, Bosch specified a non-ventilated unit, so the salt air would not corrode them out. this limited the amount of current to 11amps to avoid burning. If you have a poor battery or constantly needing to recharge it, or the regulator is over-regulating (charging above 13 .8V), then this will overwork the coils and help to cause failure. It doesnt help than in the 80s almost all Vires were built into poorly vented bays which raise the ambient temperature another 30 degrees higher (its near the exhaust). The Vire 7 is a lot more reliable for dynastarts than the vire 6 as the exhaust is cooled and kept away.

All my exchange units are fully tested.

WATER in the gearbox oil

brownish rust stain on dipstick/filler cap is a giveaway, drain and replace immediately with marinised engine/gearbox oil. if water is left in gearbox, you will end up with excessive transmission noise, then failure such as I had ; the slurry caught on the rear cone clutch and while i was motoring foreword - it suddenly seized the crank because it was now in reverse too! it took a lot of effort to get it out of gear even with the engine stopped

the cause of this problem seems to be failure of the water pump shaft seals, if installed poorly or onto a scratched or non-smooth shaft, of the two, at the outer seal lips should face outwards(stopping water ingress), and the drain hole imbetween (often blocked or rusted/painted over) should be clear (otherwise pressure build up forces water/inner seal into gearbox rather than dribling out bleed hole indicating partial failure. solution: remove water pump, gears, plate and replace outer seal with (tighter 30/14/7 is an idea) orig 30/15/7 seal facing outwards, first checking bleed hole is open (exits under pump through casting) this job can be done with gearbox in situand impellor/base plate removed ! tap in the new seal with spark plug socket and smear of sealant, then pack the spring which is visible with marine grease (this stops it rusting in years to come).

EXHAUST FUMES/SMELLY RUNNING

leaking cylinder-to-exhaust is common - remove and reseal using gasket and exhaust cement. Any leaking or corrosion near the bridging hose should be treated quickly or it will rot a big hole around the leak in the alloy. satisfactory repairs can be done with araldite and a mini drill, or get a welder to repair the area. The rubber bridge pipe should be approx 5mm longer than the gap so it is squeezed watertight, a hose clamp in the middle may help the sealing as it squeezes the hose longer.

ENGINE OVERHEATING

normal running you should be comfortably be able to put your hand on the front of the cylinder, but if it is untouchably hot - 2 things come to mind. First , is there adequate water coming out the pump? loosen the cylinder outlet pipe while running to see.- if there is no flow chances are the exhaust jacket is blocked. Second - it could be impellor failure. If you loosen the impellor outlet to jacket pipe, and while running is sprays water out, then the impellor is good pressure. Remove the rubber pipe and clear blocked pipe into jacket with a coat hanger wire - chances are this is all you need. The outlet is pumping about a pint every minute or more out the outlet

I recently inspected an unusual instalation on a 1970's Snapdragon cruiser, that used on its VIRE 6 an electric cooling pump.you can see the rusty pump on the left which amazingly was wired between earth and dynamo D+ on the regulator unit- and it worked - effectively pumping several times the designed amount of water through the head,(the vire pump was disconnected and obsolete here). i was very concerned, that this was effectively putting a low resistance to earth at D+, and would be like removing the charging/indicator lamp ., and that might prevent

the dynamo starting up at all because of their self-sustaining/strting design, BUT it actually worked fine, charging, only running the pump when the engine was on, and possibly curing an inherrent overheating problem! Note i expressed concer about the lack of gooseneck height above w/l on this instalation to prevent syphoning/sinking, also the insecure muffler fittings were leaking water badly. Note here the jubilee clip on the head's water outlet was too big a size - this caused a saltwater drip onto the carb linkages and gea parm pivot - which was making the gearstick stick badly (due to inclined shaft as normal) watch out for this as its easy to grease/WD40 the gearstick bearing and very difficult to unseize one in