Identifying 4.3L V6 Engine and one stray wire...

[imported_TheMan]

I'm currently in the final stages of completing my 3.0L to 4.3L engine swap.. I probably should have looked at this before, but oh well. The engine is from a 1991 boat and has a 2 barrel intake/carb on it. I am assuming that it is the standard 4.3L 155 HP or 160HP or whatever motor. I'll have to double check, but I believe it is non-vortec (12 bolts).

The number I pulled off the ID plate is 6D00099... or D600099? I have it written down and out in the car if that is not close enough. Just wondering if someone could confirm it is the 155 HP engine.

Afterwards I will be purchasing a four barrel intake and carb to boost it up.. assuming I read Bondo's posts correcty (http://forums.iboats.com/showthread.php?t=47268).

I'll produce some before and after pictures just for the hell of it in case anyone is interested. Fabricated some pretty decent mounts out of 6061 -T6 aluminum for my bilge area Originally I had welded up some 3/8" angle iron mounts, but they were a little too bulky. Weight savings alone is probably 15 pounds.. haha! Engine compartment is a little tight, but there is 1.5" clearance all around the doghouse. Thinking of lining the interior with some sheet metal and adding a few vent holes.

I also have one wire that I am pretty clueless at to where it came from. It runs through my wiring bundle on the engine from the rear up to near the carburetor. It is white with a blue line on it and wasn't connected at either end.. Any ideas?

Thanks guys!

SB

 

[thrasher]

Re: Identifying 4.3L V6 Engine and one stray wire...

It's probably the wire that can be wired into a low pressure oil switch to sound a low oil pressure alarm. My V6 only has the oil pressure sensor for the oil pressure gauge and a white/blue wire tied off next to the pressure sensor.

Others will chime in if I am wrong.

Gary

 

[180shabah]

Re: Identifying 4.3L V6 Engine and one stray wire...

All righty, the 1988-1992 (SN 0B773243 - 0D714106) 4.3L's have no balance shaft and were rated at 175 w/ 2bbl and 205 w/ 4bbl.

If you really want a screamer - Vortec heads and an Edelbrock IM with 4bbl would put you in the 230-240hp range.

You white wire with a blue trace on it - no clue here. If it were the other way around, blue with a white tracer, it would be your trim up wire. I just can't find where Mercruiser use a white/blue for anything.

Maybe somebody else, will know, unless the P/O fished it in there for some unknown reason..

 

[imported_TheMan]

Re: Identifying 4.3L V6 Engine and one stray wire...

Thanks for the update! I won't worry about the alarm as it does seem to be in about the right location for one..

I appreciate the advice on the screamer and will have to look into it if funds become available. More than likely I will use the boat till I can buy something a little nicer.. It is a 89 Sea Ray 180, so I'm hopin that 175 HP can move it pretty well. Top speed with 3 people and gear was 36 MPH with the 3.0L.

On a side note, I don't have the Red Mercruiser plates/stickers installed on the engine. Are the OB - OD serial numbers anywhere else or did I read it wrong?

 

[Chris1956]

Re: Identifying 4.3L V6 Engine and one stray wire...

I also think the stray wire is for the alarm system. My '88 4.3LX had a temperature sensor on the thermostat cover wired in parallel (tan/blue wire) with a no oil pressure switch on the rear of the block, behind the dissy. If the motor overheated or had no oil pressure the sensors would ground, sounding the alarm.

 

[180shabah]

Re: Identifying 4.3L V6 Engine and one stray wire...

On a side note, I don't have the Red Mercruiser plates/stickers installed on the engine. Are the OB - OD serial numbers anywhere else or did I read it wrong?

4.3L should do nicely as is, I am running a Gen2 4.3LX also 175hp(that balance shaft eats some ponies) and it pushes my 18'er mid upper 40's and will hit 50 if I'm runnin' solo on flat water.

For your SN, there should be an ID plate rivited to the block above the starter.

 

[wca_tim]

Re: Identifying 4.3L V6 Engine and one stray wire...

I can echo 180shaba. I'm running a non-balance shaft bottom end 4.3 with later vortec heads, factpry spec roller cam, edelbrock intake and 4bbl carb in a 2500 lb+ shallow v boat. It's running low to mid 50's (GPS) with 2-3 adults and a day's worth of gear and gets right up on plane even with a heavy slalom skier. and it'll run all day without emptying the gas tank (or wallet). I can imagine you'll be quite pleased with it. Good luck!

 

[wca_tim]

Re: Identifying 4.3L V6 Engine and one stray wire...

Oh, I've no idea what the wire is. On 4bbl and manifold, I wound up buying an edelbrock performer and 600cfm 4bbl carbwith the jet kit they recommend for that carb and engine combo. If you go that route, be advised that I had to go three steps up in metering rods before the jetting was right. I was kind of dissappointed when I first took it out. As I got the jetting closer, it realy woke up. I think I'm still a little lean at WOT and have one step up in mains coming for the secondaries. Overall I'm pleased as can be with it for what it is. No flat spots, great power from off idle to wot, I was skeptical about a v6, but its a great little engine and even though more power would be nice, it's just fine the way it is for now...