96 150 exedb only turning 4500 wot

[gofastsandman]

Hey gang.

1989 seacraft 20 cc
1600lbs

dry solid hull. AV plate 1 1/2 " up. SST 1 prop 15x16 no dings
Comp 105-110 all 6. Spark jumps 3/8 on all at idle.
New BRP carb kits fixed sneeze/stall issue.

New fuel tank all hoses to engine. Holds plane at 2800 at 12 mph. That`s the good news.
No anti siphon valve. New racor, BRP vro pump and Primer solenoid. Both were cracked and leaking...

On engine filter clean. All 3/8 A1 hoses.
Only rec 90 fuel. Premix 50-1 w Penn semi xlf.

The racor housing is old and shows corrosion. Could this be restricting flow/ allowing air in?

Carbs were soaked in power tune 24 hours before new full bowl kits installed. All passages clear with soft copper wire.

Plug wires seem to be original. Champ ql78yc new gapped at .030. Bottom two plugs were at .020. I did not check gaps before old plugs were installed.

Will check gaps on all new ones moving forward...

[316jughead]

You need to get a real OMC service manual for your motor, it would help a lot. Carb roller should have a plastic sleeve over a smaller black roller, check that.

[ChampioNman]

The racor housing is old and shows corrosion. Could this be restricting flow/ allowing air in?

You can always install a straight thru barb inline at the Racor temporarily and see if that helps. You're right at the end of the power band 4500-5500 is the operating range for your motor.

[gofastsandman]

Thanks.
have factory manual.
New roller w o ring.
Will bypass racor today and run her again.

Thx

[gofastsandman]

Ok, bypassed racor no change in wot rpm.

Plugs have about 15 hrs on them.
I pulled them friday. I run premix.
1 and 2 looked light to med tan
3and 4 looked med to darker tan
5 and 6 were almost black and fouled.

The plug wires are at least 11 years old and possibly original to 96.

Am I on to something?

Thanks,
gfs

[316jughead]

You may want to check that spark again, spark must jump a 7/16 gap at cranking speed. Your service manual explains how to do this and how to test the system. Plugs gapped at .020 is not good.

[gofastsandman]

I know .020 is not right or good.
My fault for letting a shop touch it.

All 6 jumping 7/16 and blue snap.
Could the original plug wires be cross talking?

[316jughead]

Have you run it after re gaping the plugs?

[gofastsandman]

Tomorrow.

[ChampioNman]

Has it always been this way or has this issue just reared its ugly head? Did you remove the high speed orifices from the carb bowls when cleaning and if so did you install all six back in their bowls and fully seat them?

[gofastsandman]

Been this way for 10 years I have owned her.Full new brp kits w bowls. New orafices seated. Timing at 19.

Idles 850 on hose 650 in gear.

[gofastsandman]

Doppler radar said no test run tonight.

I have a thought. Dangerous, I know.

Can I push the primer/key in at say 4000 and see if she picks up rpm?

[316jughead]

Doppler radar said no test run tonight.

I have a thought. Dangerous, I know.

Can I push the primer/key in at say 4000 and see if she picks up rpm?

Sure you can, no problem at all.

[gofastsandman]

Thx Jughead.

This really seems like a fuel delivery problem to me.

I`ve always run her at 3700 as she has a sweet spot there and that is close to my best economy if there is such a thing.

Cheers.
gfs

[gofastsandman]

I have a new set of plug wires coming tomorrow. I`m pretty sure the old ones are original to 96.

Now it seems we have a hurricane coming...
No testing tonight.

[ChampioNman]

Storm won't be there until Saturday run the boat.

[gofastsandman]

I want to fish tomorrow after work. The fishing here before a storm can be pretty darn good.

VHF took a dump but I have one ready to wire up in the AM.

I also have a plb, drift sock, 350 ft of rode, and a smile on my face.

[gofastsandman]

Boarding up tomorrow morning, and then going fishing! Got the new plug wires in and will retest because I`m curious.
Will report back with my findings

[316jughead]

So, you don't think that plugs gapped at 0.020, and showing signs of fouling out, could be the problem? It has to be plug wires? Of course it could be, but you had good spark. Just checking in to see how your doing. What kind of fish are you going for?

[gofastsandman]

The spark was good but not all jumped 7/16. Some only jumped 3/8.

No fishing, but happy we are not getting blown out here in WPB Fl.

Low rpms were smoother, but still only 4500. I did see 4700, but i was really trimming up to the point of ventilation.

We normally run n gun for dolphin in the am and come back to bottom fish for snapper and other friends.

Nobody was at the ramp.