115 optimax no hole shot, but full speed

[mgd7922]

Last week I took my boat out and ran it. The hole shot was slow, but it would eventually get on a plane and once on plane reached full speed. I figured I would change out the spark plugs just to try something. Today when I went to the lake the first time I took off the hole shot was perfect, got on plane as fast as usual. However, after that my boat would not get on plane without the passenger climbing up to the very front of the boat to force the nose down. Once it got on plane it seemed like it would reach full speed.
Any thoughts? I don't take my boat out as much as I want to and I feel like that is part of the problem. Before last week it had been 2-3 months since I took it out.
Thanks

[JOE54]

check for spark on all cyls , may be fouling plug on one run

[mgd7922]

How do I check for the spark?

[EuropeanAM]

Spark tester, or clip a timing light to each plug wire (one at a time) while watching for a consistent flashing pattern.

When did you last replace the spark plugs (and perform a complete ANNUAL maintenance on the engine)?

Serial Number?

[mgd7922]

2 weeks ago I went out and the boat was sluggish out the hole, but eventually got on plane by itself. Last weekend I swapped out the plugs, I used the exact same brand and number plugs which were expensive ($15 a piece). When I went out this week on the first take off it was great, got on plane quick. After that it could not get on plane without the passenger going to the front of the boat and forcing the nose down. Once it got on plane, it was able to reach top speed. It seemed like the motor had the speed, just no torque.

Serial number 1B044074

[EuropeanAM]

Verify spark as Joe suggested. Also verify you're running NGK: IZFR5J spark plugs (only correct plug).

[mgd7922]

Verify spark as Joe suggested. Also verify you're running NGK: IZFR5J spark plugs (only correct plug).

I bought a spark tester, it showed a spark on all 3.
The plugs are correct, they are that number and brand.

[JOE54]

check it when boat was sluggish ??????

[EuropeanAM]

+1... need to replicate the problem and THEN check. Timing light is often helpful (clip to one plug wire at a time while watching for clean flashing pattern).

Intermittent spark problems can be hard to catch on a traditional spark tester (especially something failing when hot, such as a coil).

Also make sure the spark plugs were properly gapped and properly torqued.

[mgd7922]

+1... need to replicate the problem and THEN check. Timing light is often helpful (clip to one plug wire at a time while watching for clean flashing pattern).

Intermittent spark problems can be hard to catch on a traditional spark tester (especially something failing when hot, such as a coil).

Also make sure the spark plugs were properly gapped and properly torqued.

Do you have the specs for the torque and gap?

[EuropeanAM]

.032-.033" and torque to 20 lbs/ft.

[mgd7922]

I torqued the spark plugs, I didn't have them tight enough. I also checked the gap and it was good.

I took the boat out yesterday and the first 2-3 times I took off it did the same sluggish start, wouldn't plane out until someone walked to the front of the boat. After that, the next 15-20 times it hit the hole pretty good. I don't think it was perfect, but it was a lot better. When it wasn't getting out of the hole the RPM's were around 3000-3500. When it started getting out of the hole the RPM's were over 5000. I don't think it's fixed. I was planning on putting the spark tester on at the end of the trip and looking for a spark during hole shot, but by the end of the trip it was taking off better so I figured it wouldn't show anything wrong.

Does that sound like anything?

[EuropeanAM]

Sounds like an intermittent problem (perhaps). Did you check your plug wires carefully for any signs of nicks, leaks, burnt spots, etc?

[Lenny_B]

Have you replaced the fuel filter lately?