Mercruiser 5.0 carb?

[pjs1183]

Hello i have some questions,
I bought a used boat to see if we would use it which we have. 97 Wellcraft 22 feet repowered 5.0 MerCruiser,
Trip one over heated, simple fix, thermostat 165 and impeller on alpha one. Prob solved.
Trip two. Bellows rip. Ok great learned how to do that and gimble. Probs prob solved. Positive not the pump works, and we didn't sink.
Trip three, performance. Won't go above 4k or 36mph. Correct factory prop. Change plugs wires cap. Way out of timing. All resolved.
Still won't go above 4k but running much better, on tank 3 of gas which is 93. Thunderbolt V ignition. Basically, stays at 10 BTDC on land. Havn't check on the water.

I believe its a carb issue. I have an electric fuel pump and looks like the port was blocked off for the mechanical one. The carb is a Rochester ( 7045114 228 4-TC) and i can't find it anywhere.

The guy i bought the boat from has basically stopped responding, he was 0 help.

Looking for the merc serial number on the bell housing i get W0268878 or something like that. I can't really tell.
Basically, were should i start?

There is a month left and then it's going up for sale but i can't sell something i know is wrong. Any help is appreciated.

 

[Bondo]

Ayuh,..... Welcome Aboard,..... Before you rebuild the carb, pull the fuel filter, 'n examine it's contents in a clear jar, for anything but clean fresh gasoline,.....

 

[pjs1183]

Ayuh,..... Welcome Aboard,..... Before you rebuild the carb, pull the fuel filter, 'n examine it's contents in a clear jar, for anything but clean fresh gasoline,.....

Has a fuel Seperator, which i replaced along with the filter on the carb. Is the redline 4100 on the 898 merc 5.0?

 

[Bondo]

Has a fuel Seperator, which i replaced along with the filter on the carb. Is the redline 4100 on the 898 merc 5.0?

Ayuh,..... I'd prop it for 4600 / 4800 myself,..... especially if it's got a 4bbl. carb,....

 

[Scott06]

You say factory prop- what pitch is it and what gear ratio do you have in the prop.

What is the total amount of ignition advance you have and what do the spark plugs look like ?

Would also think you are heading for a carb rebuild but would verify what prop is on it as it may have to much pitch.

Being a 97 boat it should have vortec heads but that would also mean no provision for mechanical fuel pump - do you know if it had 8 vertical bolts on the intake or 12 angled bolts. I don't think they did vortec engines with a Q jet - may only be an earlier 230 hp engine on a 22 ft boat may not have the right pitch

 

[pjs1183]

it’s a SS 19p. Thats all i know about it. The block is stamped 878 on both sides. I changed the plugs wires and cap then timed to 10-btdc. I used the marking on the block and HB. They were lined up perfect with TDC. I used a digital timing gun.
Plugs are good.
It refuses to go above 4k on the water. On land it will go to 5k

 

[pjs1183]

could photos to help possible

 

[jimmbo]

It has a Rochester 2bbl
Are the Throttle Valves opening fully?

 

[pjs1183]

It has a Rochester 2bbl
Are the Throttle Valves opening fully?

Looking down inside the butterfly valves open all the way.

It has an alpha one gen one stern. idk the spleen number.

 

[Scott06]

it’s a SS 19p. Thats all i know about it. The block is stamped 878 on both sides. I changed the plugs wires and cap then timed to 10-btdc. I used the marking on the block and HB. They were lined up perfect with TDC. I used a digital timing gun.
Plugs are good.
It refuses to go above 4k on the water. On land it will go to 5k

Was looking for the total advance on the ignition. Wondering if module is not advancing. You should have a total advance of around 28-30 degrees by 3 k or so rpm. 10 degrees is correct for a vortec 5.0. yours is a 220 hp engine
if you have a 1.62 drive the 19” should work fine If engine is in good shape

5 k on land doesnt mean anything as it doesnt take any power to spin up in neutral. Also becareful running to 5 k rpm on the wagon , unless you have a lot of water pressure muffs probably dont supply enough water to keep impeller from running dry …

 

[Scott Danforth]

In neutral the motor will spin to 5000rpm on 2 cylinders with a gummed up carb.

Doesn't mean anything, and you run risk of destroying the motor

Motor in pic is a vortec

 

[pjs1183]

is the carb correct?
I’ll check for advancement. I did go to 2500 with no advance. If i ground it out it goes into base mode. i guess i should start with connections.

 

[Scott Danforth]

2-barrel mercarb is correct for the 220hp. However you can upgrade to a 650cfm 4-barrel if you want which is about 240hp

 

[pjs1183]

it’s not a mercarb. its a rochester 2bbl.

 

[Scott Danforth]

it’s not a mercarb. its a rochester 2bbl.

Then someone put a Rochester on your motor. The last Rochester carbs were new in 1989

BTW, the mercarb is a Rochester clone with a single idle adjustment screw. The mercarb has a single screw

 

[pjs1183]

okay. i’ll check timing advance and get back to you.

 

[Scott06]

is the carb correct?
I’ll check for advancement. I did go to 2500 with no advance. If i ground it out it goes into base mode. i guess i should start with connections.

It wont advance in base mode. Do not put it in base mode just check the advance, just want to see if you are getting advance or not should be close to 30 all in

 

[nola mike]

it’s a SS 19p. Thats all i know about it. The block is stamped 878 on both sides. I changed the plugs wires and cap then timed to 10-btdc. I used the marking on the block and HB. They were lined up perfect with TDC. I used a digital timing gun.
Plugs are good.
It refuses to go above 4k on the water. On land it will go to 5k

did you set the engine to base mode before you timed it?

 

[Scott06]

it’s not a mercarb. its a rochester 2bbl.

It has a reman label on it. Not uncommon to see rebuild shops offering older rochester 2 jets as mercarb replacements. The mercarb was what merc started making when rochester got out of the carb business in late 80 s early 90 s. They are basically siblings. Properly set up should be ok assuming it is a marine model

 

[pjs1183]

it does not advance at all. any suggestions.