1969 85hp Starflite, ignition system change???

6

68glasspar

Seaman
Joined
Aug 28, 2024
Messages
58
racerone said:
???----If coil generates 3/8" spark , you should have spark at the plug boots.----From 1008 miles away I believe there is an issue with cap or rotor.-----Or boots where wires screw into the cap.
Click to expand...
At the plugs it won't jump over .095
 
R

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,411
Not common to go bad.----These were only used from 68 to 72 and most of these motors have disappeared.----Used parts are easy to find , depending on your location.
 
6

68glasspar

Seaman
Joined
Aug 28, 2024
Messages
58
racerone said:
Not common to go bad.----These were only used from 68 to 72 and most of these motors have disappeared.----Used parts are easy to find , depending on your location.
Click to expand...
well i was messing around with it today and i had good spark to the inside terminal of the cap but can see any way of loosing so much spark potential thru the rotor other then the rotor being bad! but i have 2 rotors and one of them supposedly was new old stock. i just have no carbon tracking on either the cap or rotors, but i just can't see any arcing even with the lights off in the shop. i'm kinda at a loss
 
C

Crosbyman

Vice Admiral
Joined
Nov 5, 2006
Messages
5,647
backtrack a bit... is this a new to you motor or when did all this problem show up. 10-15-20 KV should not any problems jumping all the way to the plugs.

anything special happened to cause it ?

Unless I missed it... you did not indicate if the sparks will jump at the boots alone. you indicated it won't jump the plugs but take one out and retest from boot ring to grd with a screwdriver.

any chance you can rig the coil output to a single plug wire and check at the plug for spark.... in effect bypassing the rotor function.
 
Last edited:
6

68glasspar

Seaman
Joined
Aug 28, 2024
Messages
58
Crosbyman said:
backtrack a bit... is this a new to you motor or when did all this problem show up. 10-15-20 KV should not any problems jumping all the way to the plugs.

anything special happened to cause it ?

Unless I missed it... you did not indicate if the sparks will jump at the boots alone. you indicated it won't jump the plugs but take one out and retest from boot ring to grd with a screwdriver.

any chance you can rig the coil output to a single plug wire and check at the plug for spark.... in effect bypassing the rotor function.
Click to expand...
With the coil wire removed, the spark will jump almost 1/2 inch with an adjustable spark tester, but going thru the cap and rotor, at the spark plug wire ends it will only jump .090 or so. The cap and rotor have been ohm checked with my fluke between terminal and no problem found. Ignition wires are solid core and ohm check good. This is the 2nd cap and rotor withe same results. Removed the stator from the dist cap so i could view any possible arc thru to that. And did it with the light off in the shop.
With all the testing and screwing around i did burn out the cdi box yesterday! So a new CDI box is on order!
 
C

Crosbyman

Vice Admiral
Joined
Nov 5, 2006
Messages
5,647
up to you but such high voltages should jump much like water flows .... so if the coil's HV voltage can't make it the the spark gap it is being insulated from reaching the ground potential it needs to return to base .

coil output is OK ....hook up a piece of plug wire to the coil or near the coil's output and connect it to a single spare plug... see if it fires. it should

if not .... the wire alone(no plug) should fire to ground anywhere on the block because we know a solid wire with 0 ohms isn't the problem so grounding may be an issue if nothing happens .

Did you recheck all grd connections points on the engine block and any other component that needs proper grounding (CDI) to allow HV return..to base :)
 
Last edited:
C

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,073
Gee, reread post #6. Those cracks in the rotors are real hard to detect and come and go with heat.
 
6

68glasspar

Seaman
Joined
Aug 28, 2024
Messages
58
Crosbyman said:
up to you but such high voltages should jump much like water flows .... so if the coil's HV voltage can't make it the the spark gap it is being insulated from reaching the ground potential it needs to return to base .

coil output is OK ....hook up a piece of plug wire to the coil or near the coil's output and connect it to a single spare plug... see if it fires. it should

if not .... the wire alone(no plug) should fire to ground anywhere on the block because we know a solid wire with 0 ohms isn't the problem so grounding may be an issue if nothing happens .

Did you recheck all grd connections points on the engine block and any other component that needs proper grounding (CDI) to allow HV return..to base :)
Click to expand...
When i receive and install the new CDI box, i will check to see if the spark will jump 7/16 or better at just the coil wire to ground, then i will attack one the spark plug wires to the coil wire and see if i can jump that same gap at the plug boot with a adjustable spark tester. that will eliminate the rotor and coil. if spark is low at the plug boot, then i would imagine the wires have some leakage to ground.
 
C

Crosbyman

Vice Admiral
Joined
Nov 5, 2006
Messages
5,647
if you carefully keep any single test wire from the engine frame there would be no " leakage" to ground through open air space. The path of least resistance ( being 0 ohms) is the metallic conductor inside the plug wire .

btw what plug type have you installed. ?
 
6

68glasspar

Seaman
Joined
Aug 28, 2024
Messages
58
i was using a ngk plug, but will probably go back to the surface fire champions. all my testing so far has been with a spark tester and the plugs not involved. I'm looking for why i dont get the 3/8 spark at the wires
 
C

Crosbyman

Vice Admiral
Joined
Nov 5, 2006
Messages
5,647
sorry to ask... how this all this come about or is this simply a new to you engine ? ...

IF " NOT NEW TO YOU" when did the problem develop ? ..... after a specific incident, engine work done, battery change whatever ...?
 
6

68glasspar

Seaman
Joined
Aug 28, 2024
Messages
58
This boat i acquired from a friend whose father bought it new in 1969. As far as the boat itself i had to cut the transom open and install new marine plywood and do 11 layers of fiberglass thru gelcoats. The engine last year ran perfect the first 2 times on the water. Then the 3rd time is was a slow no wake time and after trolling along for a bit the engine just shut off, crank no start. One paddle on board and worked our way back to the boat launch. Next day the engine started up normal. put different surface gap plugs in it and launched again. Engine power seemed reduced and after a few min's it started what seemed like miss firing. So far i have tried different plugs, cleaned the carbs, replaced the fuel pump, replaced the dist cap and rotor with supposed nos parts, replaced the battery and voltage regulator. At the start of this experiance the compressions were all around 115 to 120 cranking. The only thing i can find out of norm is the spark won't jump the 3/8 gap at the plugs!
Its been fun so far!
Also: i have replaced the wires through the timer base to the points
 
C

Crosbyman

Vice Admiral
Joined
Nov 5, 2006
Messages
5,647
OK I guess the main thing now is to restore sparks from the coil. the CDI may have blown due to the high voltage spikes going nowhere to ground as it should via plugs so further testing should be done with a means of ensuring the HV coil outputs will or can reach ground all the time..
strong EMF kickback can play tricks on delicate parts.

test the coil HV fire to ground.. .5inch away should do .

if OK try single length of plug wire to a properly grounded plug (use recommend plug type for your engine)

if OK reassemble rotor & retest with properly grounded plugs (use recommend plug type for your engine)

if you have one use the gun type spark tester (no open air testing)

just my humble opinion... that is what I would do

up to you .
 
6

68glasspar

Seaman
Joined
Aug 28, 2024
Messages
58
Crosbyman said:
OK I guess the main thing now is to restore sparks from the coil. the CDI may have blown due to the high voltage spikes going nowhere to ground as it should via plugs so further testing should be done with a means of ensuring the HV coil outputs will or can reach ground all the time..
strong EMF kickback can play tricks on delicate parts.

test the coil HV fire to ground.. .5inch away should do .

if OK try single length of plug wire to a properly grounded plug (use recommend plug type for your engine)

if OK reassemble rotor & retest with properly grounded plugs (use recommend plug type for your engine)

if you have one use the gun type spark tester (no open air testing)

just my humble opinion... that is what I would do

up to you .
Click to expand...
Thanks for your sharing your experiance!
 
C

Crosbyman

Vice Admiral
Joined
Nov 5, 2006
Messages
5,647
I am no mechanic just done lots of trouble shooting in data transmission eqpt used by Telcos and fixing up oldies (50s to mid 70s) . Some radio and TV repairs years ago... just keeping my cells going best I can at 75 :) . Fixed up some and ate crow along the way.
hope you find your problem !
 
6

68glasspar

Seaman
Joined
Aug 28, 2024
Messages
58
racerone said:
Not common to go bad.----These were only used from 68 to 72 and most of these motors have disappeared.----Used parts are easy to find , depending on your location.
Click to expand...
I'm just about to throw in the towel on this ignition system! after inadverantly smoking my cd module, i ordered the cdi electronics unit for it! First off the brass screw fitting on the end of the coil wire falls off(crimp is in the wrong place) but i push on and install the module. I check for spark at the coil wire by turning the crank with a wrench. It had great spark there. I tried a couple of times to see what i could get through the dist. cap, but ran out of time for the day. I went back at it today and rechecked at the coil wire only and nothing(no spark). i checked the DVA voltage at the blue wire to the coil and only got 4.5volt while cranking with the starter this time. So the brand new CDI electronics module failed already
 
6

68glasspar

Seaman
Joined
Aug 28, 2024
Messages
58
How possible would it be to transfer the flywheel, stator, timer base, all coils and wiring harness from a mid 70's 85hp to 115hp onto this 1969 85hp starflite? Thus eliminating the cap and rotor and points! Has it been done before?
 
You must log in or register to reply here.
Top