Spark issue with '98 Johnson Venom J200STL

[dentpusher]

Background. Engine has really never run perfect, it's always been a bit "lopey" @ fast idle and an occasional "lean sneeze" since I bought the boat in 2000 (a mechanic early on said that the sneeze was HARD to fix and suggested living with the sneeze), EXCEPT for one week, 2 summers ago. I had done my annual decarb with Berryman's instead of Seafoam and the thing ran GREAT all week. We get back down to the lake a couple weeks later for a weekend and it's running as usual again. Then last summer it ran similar, on our last weekend out until I could definitely feel a miss even underway for the first time ever and it would not rev normally like it usually does. Now I am trying to diagnose. Cold compression test revealed 95 in #6, 105 in #1 and 100 in the other 4 cylinders (lower than what I would like but no visible scuffing and cross hatching is still visible with a scope). I had some of the cheap "in line" spark testers and found #1 cylinder had WEAK visible spark so I swapped 1&3 coils and the weakness stayed on #1 so I have put it through some paces since it seemed to be more involved than the ignition coil.

I acquired an OE manual on top of my SELOC ( hate that thing ) and grabbed my multi-meter. I jumped to the flow chart and went to "No Spark on One Cylinder" and went to STEP 4. My charge coils were 120V each side but passed the resistance and ground tests. STEP 5 - Sensor coil passed the Ground Test. On the Output Test #13 I got P - .194, .183,.186 S - .193, .195, .187. On test #14, P- .852, .251, 1.021 S- 1.015, .940, 1.066. Testing resistance in Sensor Coil #16, I got readings of between 350 for the low, 2@357 on P side and 2@365 to 382 Ohms on Starboard, with my Chinese "Fluke" meter. Test #17 was 233 Ohms and there was no ground in test #18.

With the poor results I had received so far, pointing to something in the Stator, Timer base or flywheel, I wanted to confirm how poor of spark I had so I got a couple, more sophisticated, adjustable spark testers and set them to 7/16 of an inch, as suggested in some of the other threads, and found weak, intermittent spark just about everywhere at that setting, hardly any sharp snapping, blue arcing at all while cranking with the other plugs disconnected.

I am preparing to pull the flywheel. What would the gurus here look for? Are there any other tests I should do before firing the parts cannon? Will a DVA make a difference in any of my readings (my meter has built in Min/Max button)?

PS: I had a new Stator put on about 10 years ago for overcharging condition. I understand it could be bad now too, especially since I just found out how bad it was to run with wing nuts on the main battery. This is a clean looking, fresh water only motor. I have seen some ugly, crusty stuff in photos online and mine looks nothing like those salty things.

Thanks in Advance!

[ChampioNman]

Before you take off the flywheel etc, run the boat again and this time push in on the ignition key to activate the fuel enrichen circuit. See if the motor picks up or if it bogs. If it picks up then you have a fuel delivery issue, if it bogs then you have an electrical issue.
Have you adjusted the idle jets to see if the idle will smooth out? Remove the air box and start the motor at idle speed or if you can get to the RPM range where the sneeze happens then take a piece of paper and hold it over each carb and see if it gets sucked into the carb. If it doesn't you may have a reed issue. You can also look at the intake manifold and look for puffs of smoke when it sneezes. You may have a loose reed cage, a bad reed cage gasket or bad intake gaskets.
If you suspect a bad stator you can look at the top of the block for melted plastic from the coil's insulation on the stator, also look for discoloration on stator coils.

[dentpusher]

Thank you for the good advice. I will do that. I have never messed with the idle jets, taking the mechanics advice, the sneeze only happens when idling around ie. waiting for/picking up skiers. However, my last experience with mechanics (ripped off to the tune of $1300 for a bad primer bulb mis-diagnosis- not a bad VRO and carb rebuilds x6) led me to doing things myself. The sneeze was a fairly rare issue lately so I'm not sure I can consistently replicate. I will give her a shot again when we can get back on the water around here. All our bigger local lakes are so high, no one is allowed on them.

[dentpusher]

My saga continues. I took boat to local "wakeless" lake and dunked back end of boat for a preliminary test. I loaded engine down to about 3000-3500 rpm and there were no bubbles or significant vacuum pulled but I did notice the motor was surging so I decided I needed to get on open water. When there, the engine did not seem to be running well. I did not do full throttle run because it was not running "right". I wanted to check timing (which I had done @ home while idling on muffs and it was on the mark) so I shut engine down and it gave a big "HUFF" as it shut off and gas came out of the carbs an pooled in the throats but it had a whiteish milk appearance?!

After I got light connected, I restarted motor and mark was about 90* off the mark retarded (clockwise). I couldn't/can't believe the engine would even run that far off? I shut down again to limp back to ramp, but on restart, it seemed to be running better. I hooked up timing light again and now it's on the mark and running better (better as in like MY normal which was not perfection)!??? I tool around a bit to test vacuum side of fuel system and it passed fine but now its dark. I have decided to go ahead and do carbs last night to eliminate any potential fuel issues for lean melt down reasons. Now I am looking at timer base and stator again.

My questions.
-Could the engine be running that far out of time or was it the crummy 4 stroke only timing light I got from Harbor Freight because my "Professional" unit shot craps on me yesterday?

-When I did my testing of electronics, it pointed to low voltage from "charge coil" test. Does the charge coil only send charge to rectifier to charge batteries or does it have implications for spark too? I was running 14.5V charging on muffs in the driveway so I don't see how that test could be right with high voltage while running? I would be happy to read up on "Stator theory" if someone knows a good link.

I also noticed while rebuilding carbs, some of my bowl "BBs" are leaking. What is the best material to use to seal these?

I appreciate everyones' patience with my morphing problem.

[dentpusher]

Anyone?

[ChampioNman]

A bit of Marine-tex or JB weld mixed up and smeared over the BB will solve that issue. You sure you're on the right cylinder when you're shooting the timing? Which one were you on? Take the timing light back to HF and get an inductive unit.

[dentpusher]

Top right as looking at it from the rear. I double checked because it was so far off I thought I grabbed wrong one. It was an inductive HF. My replacement Innova Digital 2 stroke capable light will be here today to try it again. Thanks, Champ

[dentpusher]

Any ideas in that weird looking "gas"? It looked fine IN the carbs.

[ChampioNman]

It appears to be water mixed in with the gas. A leaky power head to mid section gasket will do that.

You need to confirm TDC on #1, bring the piston up to the top of the stroke and compare #1 to the timing pointer. One of two things could possibly have happened the flywheel key may have gotten sheared or the timing collar on the inside hub of the flywheel has loosened and rotated.
You can down load the CDI troubleshooting manual and it will show you how to check the collar along with other troubleshooting tips for your engine, for free. http://www.cdielectronics.com/troubleshootingguide/