Blaster acting weird, under power (sometimes)

[osullivan]

Ok, here’s the issue;

Blaster when I start out is “ offing when starting off. It doesn’t jump out of the water and doesn’t have full power. I get up to speed and run around lake and goof off but when I do 180s it falls on its face, It offs down so much I can’t side mount either as in deep water start.

This is has happened the last 5 times out. The odd thing is at some point later in the day right before I run out of fuel the dang ski runs like a champ. 100%.

Then it’s all over and I’m out of fuel. Here are the following repairs we have done and still acts exactly the same;

Rebuild carb
install different rebuilt carb
clean carbs again and no issues found
New fuel filter
drain fuel and add ethanol free fuel
new plugs
fuel draw test (checks out never changes on res or on)
new plug wires
new ecm
new voltage regulator (when running the ski was jumping around on voltage like crazy) fixed now.

now the weird stuff

installed known working stator and the ski would t start

re-installed old stator and ski started back up like normal

went back out and the ski still is not running at full power.

Please, any help would be greatly appreciated.

Disclaimer, motor was rebuilt at full bore by previous owner and has great compression. I have also upgraded prop and when the ski was running 100% and all checks out there as the ski was a blast.

[hemmjo]

Are these typos? not sure what this means " offing when starting off" or, "It offs down so much..... "

If you can be more clear about the symptoms, you will get better advice.


After it runs out of fuel, have you ever put in just a little fuel and gone back out to see if it still runs good when the fuel level is low?

Do you have a fuel shut off valve? When tank is full and it does not have full power, try closing the fuel shut-off slowly to see if it runs better just as it starts to lean out from lack of fuel.

[osullivan]

Sorry about typo;

It is bogging down. Think in terms of running at 40% reduced power all then time. Then, out of nowhere the ski hits 100% power and runs flat out, i can do 180s and stand it up and do side starts like normal.

Then the ski will just die. I baby it home on reserve and then head to the house.

I have not tried the fuel shutoff valve to try and reduce fuel but will. I also have not tried to fuel back up with just a tad of fuel. I can try that also.

Is there anything in the tank that could be cashing this?

Thanks

[needforspeed]

how old are the fuel lines? Maybe you have a split in the tank pick up? Maybe your vent check valve is not working correctly... Just go through that stupid stuff first. I like to go through all the stuff that doesn't cost money first...lol

[wmazz]

Then, out of nowhere the ski hits 100% power and runs flat out, i can do 180s and stand it up and do side starts like normal.

Then the ski will just die.

Please describe how the engine dies.


Bill M.

[osullivan]

Fuel lines are 2 years old. I’ll check the vent tonight.

How might I check the fuel pick ups?

[osullivan]

When the engine dies, it’s when I’m running full out (ski is running normal) and the. It just shuts off. Meaning the engine just quits running. I push the start button and give it some gas and it fires back up. Then I switch to reserve and get to the dock.

[wmazz]

When the engine dies, it’s when I’m running full out (ski is running normal) and the. It just shuts off. Meaning the engine just quits running. I push the start button and give it some gas and it fires back up. Then I switch to reserve and get to the dock.

That sounds like it is a WOT seizure.

Please check your compression, a 5psi difference in compression may
be important. Often a seized cylinder will test the same as a normal
cylinder.


Bill M.

[osullivan]

so here is the update,

Prior to heading out I checked compression; 148 on front and 147 on rear for compression.

I removed spark arrester cover and noted a high amount of oil on the flame arrestor grids. Enough so I could tell the oil was red/purple.....

I should also note prior to starting the battery read 12.7 amps and once started remained at 13.2.
I cleaned this up and began the process of removing the oil pump.

I removed oil pump and installed a block off plate. I'm mixing at 50/1 and using Klotz.....

The first hour of running around on a full tank of pre mixed fuel was still running sluggish. I could not do a side mount..... upon reaching half tank (estimated) ski ran on one cylinder.....

I jumped off and reached into engine and noticed rear spark plug was loose, pushed back on and then was off again.

Ski ran better today than it has in some time now.....

Is there a chance that the factory oil pump was pushing too much oil and causing the ski to run poorly?
does this make any sense?

thanks everyone.

ds