lost another power pack(sierra helped)

1989 90 hp johnson. boat has sit for about 6 year, took off carbs. and clean them all up, new plugs, within about 10 min.s the motor was running, all 4 cyl. were getting warm, then cyl. 2-4 started getting cold. took out both plugs and checked for spark and had no spark.I checked the stator and had 180 volts 530 ohms. checked timer base and had from .7 to 1.6 volts and 42 ohms on all 4.I swaped the coils from 1 side too the other an no change. next day I put the coil back were they were and tried starting the engine again and it started up but after a few min.s 2-4 lost spark again, I rechecked everything again and had the same reading, so I tired starting it again then had no spark too any cyl. Power pack was dead, traced it too a bad coil(had no ohm reading at all). Replaced all 4 coils ,new wires and a new power pack. rechecked all reading and still had the same results so i started the motor, all 4 cyl. had 178 volts at coil, then cyl. 4 died an cyl. 2 has a very weak spark. the power pack is dead for cyl. 4. cyl. 1-3 are running great.I am at a lost and running out of money too put into this motor. any ideas.......
rechecked everything again today cyl. 1-3 hitting good and cyl. 2 has good spark and cyl.4 still has 4.4 volts at coil... stator and timer base both read within spec's

Re: lost another power pack

Re: lost another power pack

I was chasing electrical problems with my 1990 25HP, see the post for "1990 25HP electrical puzzler." Turns out that the new coils have a grounding tab that was not getting a good ground. I thought I had gotten a bad power pack. Got advice from another poster -Cofe- who told me to check insulation on the coil mounting bolts. I had mounted them with insulating washers when, in fact, they needed to be grounded. That fixed the problem. SOmething to try. Good luck.

Re: lost another power pack

Re: lost another power pack

Any voltage riding the kill wire to the power pack will damage it. This often comes from faulty wiring or from a bad ignition switch. It can also come from connections that have corroded in areas like the big red plug at the engine and from damaged wiring in the engine harness.

Failing ignition coils are often causes of repeated powerpack failures as are failed rectifiers; you should bench test both components before returning the engine to service.

Re: lost another power pack(sierra helped) update

Re: lost another power pack(sierra helped) update

I tried the big red plug and still no fire at cyl.4. disconnected rectifier and still no change. I had tried the power kill wire an it had no voltage at all. I took the power pack wire from cyl. 2 an swaped it with cyl. 4 and had 168 volts on 4 and 4.6 volts on cyl.2. all of the wiring looks very good, I had the flywheel off last week an it was in very good shape all wires looked very clean. I have only had the 1 coil go bad (it had zero ohm reading) but replaced all 4 for safe measure. the power pack had no fire too any plug. now I have fire to 1,2,3 nothing on 4. I notice if I ohm check the power pack between the white and red wire I get no reading at all, all other wires show a reading. the timer base has a good reading of ohms an volts....... I was at a total lost on what too check next so I wrote SIERRA about the power pack an this is what I got.(Dear Sir,

I believe you have a defective pack as well. The circuits inside the potting could have failed for the one cylinder. You can either take this back to where you purchased for an exchange or, return directly to Sierra for an exchange) what a great company.I never onace asked too have it exchange just told them the problem I was having and showed them what I tested an ask if they had any idea what was causing this problem.I am going too be a neverous wreak hooking up that new pack, I have been thru this thing thing for weeks now and just don't see anything that could burn up that powerpack for the 1 cyl.

Re: lost another power pack(sierra helped)

You "tried" the big red plug, did you disconnect it and try jump starting it?
(choke it with your hands to stop the engine).

Re: lost another power pack(sierra helped)

yes, and no spark on cyl. 4, 1-2-3 all have good spark 168volts +......cyl. 4stilled had 4.5 volts with motor running.........