OMC 4.3= No power

[dodgezilla04]

I might be missing something simple here.
1987 18' Searay cuddy. has a 175hp OMC 4.3 Chevy V6, 2 BBL.
Boat was not maintained well, and sat for 4 years. so i started out with everything since it wasnt running.

Had the Carb rebuilt and calibrated by a shop in Seattle
new cap, rotor, plug wires, plugs, condensor, points, filters... set the dwell at 39*, timing at 10*btdc.. compression is 155-165psi. firing order is correct.
warmed it up, changed oil and lube filter. adjusted the shift cable, it was idling on 3 cylinders, now is fine.

drained the fuel tank completely. checked the vent for obstructions, none there.

starts quick, idles really smooth, runs well. here's the problem. it has no power.
not in gear it will instantly rev up to full speed, no hesitation.
underway however, its really slow to get up to Rpm(and plane out) and only reaches 3400rpm. moving the throttle to full just doesnt do anything, it will not gain rpm. Top speed is 29mph, this boat used to make 37mph several years ago. The prop is the same that has always been on there and is not damaged.

the fuel pump appears to be keeping the bowl full, i am going to install an inline pressure gauge between the pump and carb, hoping to see around 6psi.
what am i missing????

this being a 22 year old boat, is it possible that the foam is waterlogged and she's just too heavy?
what should this boat weigh? i can go weigh it and the trailer, then just the trailer to check its current weight....

i'm missing something here. help please?

 

[dodgezilla04]

Re: OMC 4.3= No power

oh yeah. i am NOT the owner, just the friend of the owner who intends to use the boat as well. i did not neglect it all these years, the other person did.
thanks......

 

[dodgezilla04]

Re: OMC 4.3= No power

the boat has always been stored outside, and the bilge is dry, but that doesnt mean the foam isnt full of water does it?

 

[peanutbay1]

Re: OMC 4.3= No power

It sounds like your are over pitched on the prop.

What pitch is on the boat now?

As far as the foam in the boat. The marine manufacturers use special foam that will NOT collect water. I am not saying you dont have water around the foam but as far as soaked in that is highly unlikley. It sounds like you have a higher HP range prop on your boat which will make it a slow plaining dog out of the hole.

 

[dodgezilla04]

Re: OMC 4.3= No power

as stated, 18'. same prop that's been on there for 11+ years, ran 37 with that prop before.
Nada guides say the boat weighs 2300 with a 350, so with the 4.3, slightly less. single axle galvanized trailer might weigh, 800lbs....
so 3100 give or take.
i am gonna weigh it tomorrow in the a.m. guess i'll know then.

thanks guys.

 

[danond]

Re: OMC 4.3= No power

As far as the foam in the boat. The marine manufacturers use special foam that will NOT collect water. I am not saying you dont have water around the foam but as far as soaked in that is highly unlikley. )

That's misinformation. You clearly have never restored an old boat. The foam degrades over time and absolutely will absorb water, making the boat tens to hundreds of pounds heavier.

 

[dodgezilla04]

Re: OMC 4.3= No power

Weighed the boat and trailer saturday... total weight was 3350 lbs. that's the boat with 20 gallons of fuel, and a 40lb anchor, the trailer is a single axle roller,....
so the weight it what it should be.



another dumb question...
i have autolight 24 plugs in this thing.... is there a different plug i should be using?
thanks

 

[bruceb58]

Re: OMC 4.3= No power

Double check the firing order. It is very easy to miss this and the engine sounds pretty good still.

Also, check that you are getting ful spark advance. Could be that the distributor weights and sprngs got corroded over time and is not giving you full advance. You will need an advance timing light to verifythis.

 

[rs2k]

Re: OMC 4.3= No power

Check compression and make sure that applying full throttle to the level makes the carb go to full throttle.

 

[dodgezilla04]

Re: OMC 4.3= No power

gents, while i appreciate the responses, i stated in my initial post about the firing order, the compression numbers, the fact that the prop wasnt changed,the boat length, etc..... what's the point of typing out ALL of the info, if it isnt read???????

the question asked was what is the needed gap?
if this irritates you fellas, sorry...

 

[rs2k]

Re: OMC 4.3= No power

what is the needed gap?

≠

i'm missing something here. help please?

I still recommend you check compression on ALL 6 cylinders and make sure that applying full throttle to the lever makes the carb go to full throttle.