tearing my hair out- new packs, trigger,stator - STILL intermittent miss. 85 blackmax

[gmacrae]

Like Capt says, be weary of that inductive pickup not being as accurate as you might think. They can definitely miss some sparks and pick up other leads if you're not real careful.

A couple years ago I had a coil wire that was broken inside the insulation (right by the coil terminal) and was giving me intermittent spark, that was a bastard. Maybe crimp new terminals on at each coil and at the switchboxes just in case?

[gmacrae]

Also, one thing that helped me greatly track ignition problems was a cheap little "automotive" multimeter with inductive pickup and tach readout. This is the one that I got if you wanna try find one similar: https://www.jaycar.co.nz/automotive-...ickup/p/QM1444

[Motv18]

Tracking both post is rough I’ll stick it in this one as well.

Some service books spec high side at 20-90v at crank- idle. At 200v it’s probably either burned some capacitor in support of the 200v on the low side (to many amps) or one of the loops of voltage is to high to the scr or bias.

Which is possibly the cause of one white white on the boxes being 15v and other white on opposite box 4v I think that the one with 1-30v spec.

I hate tracing volts paterns in the switch box to box to see what’s hooked to what.

Someone will I’ll have to confirm that this particular system on your engine matches thoes specs. And such.

[Motv18]

Supporting documents

[Fstarockr]

thanks - we dipped it in the water this evening and it seemed to have pretty good power.. im gonna do a water test 2moro or the next day and see how she runs- the flywheel looks so good.. either way will see.

Im getting a sneeze from the carbs at idle.. cant remember if these carbs have mixture screws but i believe not.. add a little more timing or open butterflies?

whats a good idle spec? currently around 4-6 ATDC iirc.. i usually set it up to buzz the timing a little before the primary pickup..

[Fstarockr]

good info fellas - I do have a MM with tach.. Motv18 - those readings were from the older packs.. i have run the the new ones and all is fine..

Could a carb sneeze mimic an intermittent spark? The carbs tend to sneeze once now and then before 100% warm.. should I open butterflies a little more or add/remove advance perhaps?

Soon as the thunderstorms have passed we are going on water for a proper test and some tuning and will see! I spoke to a guy today who said if the flywheel was bad (cracked/moved magnets) the motor would be firing all over the place and run terribly - soon as Im back from the water ill report back..

fyi WH22 carbs- rebuilt them 5 months ago with OEM kits- they seem totally fine, no leaks.. usually fires right up instantly when warmed a bit.. anyone got a ball park idle timing for these? currently at about 6 degrees ATDC at around 900 (out of gear)..

[gmacrae]

good info fellas - I do have a MM with tach.. Motv18 - those readings were from the older packs.. i have run the the new ones and all is fine..

Could a carb sneeze mimic an intermittent spark? The carbs tend to sneeze once now and then before 100% warm.. should I open butterflies a little more or add/remove advance perhaps?

Soon as the thunderstorms have passed we are going on water for a proper test and some tuning and will see! I spoke to a guy today who said if the flywheel was bad (cracked/moved magnets) the motor would be firing all over the place and run terribly - soon as Im back from the water ill report back..

fyi WH22 carbs- rebuilt them 5 months ago with OEM kits- they seem totally fine, no leaks.. usually fires right up instantly when warmed a bit.. anyone got a ball park idle timing for these? currently at about 6 degrees ATDC at around 900 (out of gear)..

I think the manual will state 8* ATDC idle timing for yours (idle stabilizer unhooked), but most the old pros in here say to kinda use the idle timing to get your idle speed right and where you're happiest with the quality of the idle (anywhere between 8* ATDC and 0*) which I've found to be good advice.. I have mine at about 4*ATDC currently - seems real happy there

[Motv18]

Carbs are simple but a lot of possible adjustment.

The closed butterfly stop can can be used to up the idle, not recommended.

Run a check on the idle jets to check p/s positions easy to flip them. Mix screws out the recommended starting amount. Idle time sorta the middle of the road.

I verge off here and use time for large adjustment, stop for 25-50rpm and any mix screw for less then 25rpm. Just because 1.5 off what you felt as lightly seated isn’t all that accurate. Most times a 1/4 turn has no effect or brings it in line.

[Merc 2.5]

Wh22 has no adjustments really , except float adjustment. the idle will b adjusted with timin as long as plates r closed. the pick up tube that feeds idle circuit can easily get clogged or u have a misfire sumwere or possible bad reed. Now on 1st initial start up dead cold , it's common it will sneeze until all cyl start getting all its fuel and building little heat. after that it shouldn't sneeze at all. These r just my experiences with the carbys. Wh carbs are very very simple

[Fstarockr]

MAJOR update - took the boat out.. started/idled well -with an occasional sneeze.. off idle had a bit of a flat spot but the mid and top range was insane - just ran an like an animal with instant response..

However after about 5 minutes heading back it started sneezing alot more.. now and then it would stall. naturally i tried fiddling with the timing/pickup but couldnt dial it out. At one point the sneeze came right through the air baffles onto my hand so im very convinced the reeds might be the issue.



I have a new reed block with carbon reeds on its way which i found for 80 bucks total and couldnt pass it up - is there anything i can rule out before doing reeds? I think now the intermittent spark I was chasing all over town was possibly in fact a sneeze issue?







PS: I was told the powerhead was rebuilt by the previous owner (about 2 years ago) so im sure the crank seals are ok..

[eli]

Huh?

[Motv18]

Check for lean att idle, lean sneeze will break reads.

[Fstarockr]

Check for lean att idle, lean sneeze will break reads.

not sure how to check this? no adjustment on carbs. going to pull carbs and hopefully see a blocked emulsion or idle jet, otherwise I'll look for Reed issues and put the replacement block/reeds in..

they are carson reeds

[Motv18]

The idle air jet would be to big is all I can think of for lean idle. Unless theirs a leak but I don’t think your idle ran away.

Thats just the normal progression of events that lead to a busted reed. Not the only way.

You can catch hot exhaust and (backfire) that will damage reeds as well.

When end I went to school we focused on why a lot of times instead of just saying put that part on, its a bad habit when the small talk isn’t proper. Good idea to check though as new reads will fail with it still sneezing. Or whatever cause the reed to fail. It’s possible that’s taken care of though with the other repairs you have completed.

[Fstarockr]

The idle air jet would be to big is all I can think of for lean idle. Unless theirs a leak but I don’t think your idle ran away.

Thats just the normal progression of events that lead to a busted reed. Not the only way.

You can catch hot exhaust and (backfire) that will damage reeds as well.

When end I went to school we focused on why a lot of times instead of just saying put that part on, its a bad habit when the small talk isn’t proper. Good idea to check though as new reads will fail with it still sneezing. Or whatever cause the reed to fail. It’s possible that’s taken care of though with the other repairs you have completed.

yeah i was wondering that.. when i have the carbs off ill check the jet sizes.. might have been leaned out for altitude, not sure- reeds and block on their way. ill update when i have some hopefully good news..