need some help with my rig

[Ajskennels]

my 225x burnt 2 pistons and is in the sleeve shop at the moment so i hung a 96 200 efi on my 98 202 blazer, can't get it to twist but 4k rpm, prop is a 25p OEM prop, prop is 1" below the pad and its on a 12" hydro dynamics jack plate i use to have the same rig on a 94 stratos 284 but with a 6" jack plate and could twist it 6k, the boats weigh about the same with the stratos a little heavier, the blazer is 20' and the stratos was 18' would that 2 extra feet that the blazer has on the stratos be the reason, all the prop calculators online say i should be running a 26p with this engine on the blazer, any thoughts

[Go Time]

Give us something to work with. Check ignition and compression on all 6. Look for fuel restrictions...

[90 5.0]

Should turn more than that, check all the basics first.
Check for wot
compression
fuel pressure
spark
timing
tps
battery voltage @ wot(incorrect voltage from regs can make ecu go pig rich)

[Ajskennels]

Compression- 125-130 all 6
Fuel pressure- is about 40psi, havent checked while running at wot
Spark is good, bright blue across 7/16 gap
Timming was set on the ears at 23deg atdc
I havent checked tps yet but i suspect it to be off
Voltage at wot shows 14v
Regulators are brand new so should be fine

[Ajskennels]

Its only at around 3/4 throttle at 4k, it has a hesitation if i hold it to the floor

[Go Time]

Check fuel pressure at 4K using schrader valve on VST. Check ignition output with DVA of hi output of stator > 2500 RPM. If you have access to a DDT, check ECU sensors for tpi, temp & map.

[racervboat]

post #4 you say 23 degrees atdc? sure you don't mean btdc?

[Ajskennels]

Yes, dident realize it till u said it but its btdc, pickup timing is around 2 deg atdc

[Ajskennels]

ok, so i did a fuel pressure check with the engine running and while at idle it holds at around 35psi, but when i rev it to around 2k it drops to 30ish psi, i have not done a dva check on the stator because i don't have the equipment and I'm not sure what ddt abbreviates to, my shop manual doesn't say what psi it should run at WOT just says 34-36 psi

[90 5.0]

Should be close to 39 psi all the time.

You got a fuel restriction , a bad reg or a bad pump

[Ajskennels]

Im not real sure how accurate the guage i was using is but either way the drop in preassure shouldent be there correct?

[Go Time]

That engine has a 36# regulator....but you should not see the 6# drop. I agree you should check for fuel restriction. Check pulse pump, primer bulb, anti syphon valve for a few....

[W2F a V-King]

Does anyone make a good adjustable regulator for these motors?

[WillySteve]

Does anyone make a good adjustable regulator for these motors?

I've run a 39# Bosch Reg off of an old Volkswagon for years. Exact same design as the original Merc and it has a small allen head screw inside where the vacuum hose plugs in for adj!!! I never checked the original but it should also!

[Ajskennels]

I think im gonna do away with the vst tank all together, anybody know how to go about doing this?

[W2F a V-King]

http://www.screamandfly.com/showthread.php?312257-Pro-max-VST-delete&highlight=VST+Delete

Good Place to start ^^^..TexasVector has done it.

James

[skeeter91]

ive done it on my last two boats,make sure you have a way to plumb a return fuel line to the tank.Also,you should run the pump off a relay that also is wired to a two way kill switch,you dont want that pump running if there is an accident!

[Go Time]

Look up pro stock fuel system here. The only part people debate is the best fuel return to tank method

[Ajskennels]

Anybody know what fuel pressure the A8 box runs on, i cant find it, found out my box is from a xri, not sure if it makes a diffrence or not

[90 5.0]

Anybody know what fuel pressure the A8 box runs on, i cant find it, found out my box is from a xri, not sure if it makes a diffrence or not

all xri run a 39# fuel curve

[90 5.0]

I think im gonna do away with the vst tank all together, anybody know how to go about doing this?

http://www.diamondmarine.com/web_pages/Fuel%20System.htm

[Ajskennels]

could the Tps sensor cause my problems, because it was way off, or a combo of both, like i said I'm not real confident in the gauge i used for fuel pressure to be really accurate

[idvette]

What caused the original issue, the 2 burned pistons? Did it lean out?? Fuel system is easy to go through, check it from pickup in tank to motor.

[Ajskennels]

ok guys found the problem i hate seeing threads where the OP never says what the problem was so here goes, i decided to check the timing again after i have already pulled my hair out checking this and checking that and was just getting ready to start on my teeth, turns out that while i was checking it i was able to hold the advanced timing stop against the stop with my hand, but while under way with the throttle cable it wasn't touching the stop, therefore wasn't advancing the timing and was only running around 8 deg atdc at WOT, took the arm apart and got all the gummy mess and grit out of it, and its perfect now, twisted what i believe to be a old laser prop ( a40) 25p to 6100, don't know the MPH, last i seen it was 66 with my phone gps but had to lay the phone down and use 2 hands, still had a ways to trim out but I'm guessing low to mid 70's with the current setup, anyways thanks everyone for your help

[Ajskennels]

the 2 burnt pistons are in my 225x, its the height of fishing season down here in mobile so i stuck this 200 on here to get me thru fishing season, but on the 225x i believe the ecu was the cause, the tech at the repair shop i took it to couldn't communicate with it so thats more than likely the problem, I'm converting it over to cdi ignition and slapping a promax a17 computer on it when i get it back