Crossflow Power Slipping

[fishinscott]

It's been a while since I've posted here, but that's a testimant to the moderators. My XP150 has been running great since you fellas helped me with servicing the fuel scavenging system. However, I seem to have lost power since then.

First off, here are the particulars regarding the motor and service history:

Model: TE150SLCEM
Serial: R08241230
Boat: 1990 Nitro 185 (18' 10")
Mount: Mechanical Jacking Plate
Prop: 3-Blade, 22 Pitch Raker

Service History:
Sep-2002: New Powerpack
Feb-2005: New coils, plug wires, fuel scavenging valves, fuel recirc hoses.
Feb-2005: Rebuilt carburetors, including flattening float bowls.
Annual: Decarb and replace plugs

Symptoms:
Hole shot has been getting consistantly worse over the past 7 or 8 months. It is to the point now where it's okay when I'm by myself, but if I have a passenger and full livewells and fuel tanks, it won't get up on plane (without the passenger moving towards the bow). In the past, the holeshot was a little sluggish, but I could hear the motor accelerating right up until it got on plane. Now, if the boat's loaded, it will wrap up to approximately 2000-3000 RPM (estimate, tach doesn't work), and stay there until my passenger shifts to the bow helping the boat get over.
Once it's on plane, everything's great. It tops out at about 62 MPH, and runs very smooth. It idles pretty well, although sometimes it dies with a loud spit. On cold startup, it needs a lot of priming, and takes about 20 seconds for it to fire up.

Sorry for the long post, but I'm hoping it will save you all time in having to ask me a bunch of questions. Thanks in advance for what I'm sure will be helpful information!!!

[SRP71]

Have you checked compression? Before rebuilding my motor it could do 65 on top end, pull a skier ok but as the summer progressed it got worse. Without a load it still would accelerate fine and still would do 60 to 65 with 2 to 3 passengers. Try to pull a skier and it was the weakest boat out there. Motor wouldn't get over the hump.. (max RPM 2000 to 2500 Rpms) What a Slug!!! When I tore down motor it had very bad scoring on one hole and low compression on all cylinders. Lived one summer on a tired motor. Purchased it in fall and by next fall it was due for rebuild. I knew it was tired when I bought it but tried to get as much out of it before I tore it down.

Amazing how they will still run with low compression. Put a load on them and they fail terribly. This was on a 19' ski boat that was loaded with gear all the time.

I would check compression first if you havent already and post numbers, the experts can tell you what to do from there.

Just a thought hope it helps


Scott

[RUSTY63]

Do your storage boxes look like Bass Pro Shops inventory?

[fishinscott]

Good thought!! The compression is running between 85 and 90 PSIG on all cylinders. I looked for a compression value in the manual, but all I read was that the important thing was that they were within 10% of each other. The compression hasn't changed since this problem started developing.

[fishinscott]

I don't have a lot of gear on the boat. I've got 5 Plano 3500 boxes with various tackle. I've got a net, 8 rod/reel combos, a small tool box with required safety items and some basic hand tools. I don't even pack along an anchor or a spare prop.

I've never actually weighed it, but I'm guessing my gear weighs less than 150 lbs. Another thing I considered is the possibility of water getting in and saturating the foam & wood in the hull. I pull the plug after each use, and usually their's just a small trickle of water. But, could there be some kind of breach that's allowing water to just soak into the hull? Do you think I should go to the scales and see what she weighs?

Is there a way to determine what kind of power the motor is putting out?

Thanks!!

[ChampioNman]

You can have it dyno tested at a Hop up shop if there are any in your area.

[fishinscott]

I haven't located anyone locally that can do it. Are there any kinds of tests I can perform on my own the determine whether the motor is performing up to it's potential?

Thanks!!

[ChampioNman]

You can do a leak down test on it, will tell you more than a comp test. A good shop can perform this test for you.