Keithm18
Regular Contributor
Hi All. this is a follow up thread to the one I posted a few weeks back.
Managed to get the boat back in the water today. Johnson 90hp 1981. Carbs rebuilt, fuel new, compression good (all indications are boat should run well) on last outing was down on power after Carb rebuild had cured it stalling when going to WOT after starting. thought it was a fuel delivery issue.
Turns out it's not a fuel delivery issue. I used a timing light with engine at idle in the water to see if all pugs were firing and they do, but one seems to fire intermittently. If you face the motor from the rear of the boat the one on the bottom left appears to have spark for a few minutes and then die out. I checked and confirmed all electrical connections are good. I then swapped out the power packs and the problem then moved to the right bank bottom cylinder. So I think that the power pack may be faulty.
After the swap it ran ok for two minutes at idle. I connected the timing light to that cylinder. It shows spark, but when the engine seems to miss the light seems to miss, but then It fires a little and then after a few more minutes it dies altogether.
my questions are as follows:
1) does this sound like typical behavior for a dying power pack?
2) are there any tests I can to with a multimeter to check if this is the problem, before I invest in new packs, because they are very pricy and I don't want to buy parts if it may be something else causing this.
thanks.
Managed to get the boat back in the water today. Johnson 90hp 1981. Carbs rebuilt, fuel new, compression good (all indications are boat should run well) on last outing was down on power after Carb rebuild had cured it stalling when going to WOT after starting. thought it was a fuel delivery issue.
Turns out it's not a fuel delivery issue. I used a timing light with engine at idle in the water to see if all pugs were firing and they do, but one seems to fire intermittently. If you face the motor from the rear of the boat the one on the bottom left appears to have spark for a few minutes and then die out. I checked and confirmed all electrical connections are good. I then swapped out the power packs and the problem then moved to the right bank bottom cylinder. So I think that the power pack may be faulty.
After the swap it ran ok for two minutes at idle. I connected the timing light to that cylinder. It shows spark, but when the engine seems to miss the light seems to miss, but then It fires a little and then after a few more minutes it dies altogether.
my questions are as follows:
1) does this sound like typical behavior for a dying power pack?
2) are there any tests I can to with a multimeter to check if this is the problem, before I invest in new packs, because they are very pricy and I don't want to buy parts if it may be something else causing this.
thanks.