My 5.0 to 5.7 swap log

[alldodge]

Looking real good and glad your ready

One comment, it's my understanding that steel braid covering is not allowed by USCG regs. The fuel line must be able to be inspected without removing cover

 

[sub2010ss]

Been watching your thread.
I installed a RapidoMarine 5.7 Vortec a few years ago (~450Hrs)....no issues so far.
Hope all goes well today.

Thanks! That's good to hear. She ran amazing today. Was out in the lake for probably 6 hours. About my only concern right now is the fuel level indication and a hard start after she been running awhile. Starts up smooth the first start and then struggles after that.

 

[sub2010ss]

Looking real good and glad your ready

One comment, it's my understanding that steel braid covering is not allowed by USCG regs. The fuel line must be able to be inspected without removing cover

Thanks. I went back and forth on the fuel line being braided. I'm actually still airing on a few connections for my pressure regulator and then I can switch to steel if I decide to.

 

[alldodge]

Thanks. I went back and forth on the fuel line being braided. I'm actually still airing on a few connections for my pressure regulator and then I can switch to steel if I decide to.

You can use rubber fuel line, it doesn't have to be steel. The reg is so it can be inspected. Merc uses steel lines but not because they have to.

So far as the hard starts when warm, do you think it might be vapor locking issue?

 

[sub2010ss]

I don't think it's vapor lock. It's more like a weak battery. But the battery is charging at 13+ volts. Once it's hot it slowly cranks then speeds up and then starts. Strange.

 

[Bondo]

I don't think it's vapor lock. It's more like a weak battery. But the battery is charging at 13+ volts. Once it's hot it slowly cranks then speeds up and then starts. Strange.

Ayuh,.... Could be, water in the cylinders,....Hot Timin',.... or Bad battery cable connections, (+), or (-),....

 

[sub2010ss]

Thanks Bondo. I'll check those out today.

 

[sub2010ss]

Ok, I checked the timing and its dead on 8* BTDC. Connections are tight and clean. I checked all of the plugs and couldn't find any indications of water. Plugs looked good and brownish. Im going to upload a video. This was one of the better starts after it warmed up. Is there a better way to check for water in the cylinders?

 

[sub2010ss]

Couple of pics of us out on the lake.

 

[jarruiz13]

Congrats overall. Whats your top speed so far? I hope you are able to solve the issue because i have no clue unless you are idling to low.

 

[sub2010ss]

Thanks! I hit 45 but I'm hesitant to stay there very long or push it too hard. I know its got more in it but it'll probably need a prop change so stand by for future post. The idle is set right at 700-800 rpm. Im looking into getting a new starter as Im thinking that may be the cause.

 

[alldodge]

After a run and shutting the motor down look down the carb and see if you see any fuel dripping.

 

[sub2010ss]

Will do! Although this happens in and out of the water. What would cause fuel to drip?

 

[alldodge]

Will do! Although this happens in and out of the water. What would cause fuel to drip?

If your carb needle seat is not sealing off, it will leak. The repair is to readjust the float bowl level or replace the needle seat and valve

 

[sub2010ss]

I see. I'll definitely check.

 

[jarruiz13]

So have you had any further issue? Were you able to solve the issue? In a few months i am going to need to buy a motor and rapidomarine sounds like a good place to pick one up.

 

[sub2010ss]

Sure did. I cleaned all the cables with 40 grit sandpaper, reassembled and picked up a high torque starter. We were out on the lake again today and she sound like a champ and fires right up. So extremely happy with the boat and the results. We've done a few higher speed passes and was able to hit 53mph on the gps. Not sure how that compares to the 305. It's got kind of a pop at that speed which I thought was a rev limiter but apparently not. I wouldn't really consider that a problem as I'll never stay at that speed for long. Was more curious. Also still learning some things like, maneuvering, out the stern drive up when leaving the water, don't forget anything in the truck, those kind of beginner things.

I'm very happy with the final product on the rapido. I would probably consider going with a crate auto engine next time and swapping the cam and frost plugs. But that's mostly because of the shipping issues I had. Feel free to hit me up when you get into it and I can give you any more insight I have. It's been fun.

 

[JaCrispy]

I was going to mention the starter. I rebuilt a 440 Chrysler for my car years ago, wouldn't start or barely started with a standard starter. Had to buy a high torque like you did, no problems after that. I think I wasted 4 starters in a month.

Is the Edelbrock working good out-of-the-box? Just screw tuning?

 

[sub2010ss]

I had all of these ideas in my head as to what was going on with the starter. Fresh machine work, higher compression, either way the new starter is great!

So far no problems, I honestly don't know much about tuning these carbs. Worked with Holley's all my life. I followed the idle tuning that came with the instructions. It seems to have plenty of power throughout the power range. Still looking into a surge or poping at high rpm but I'm not willing to stay there long right now. The only problems I ran into with the new carb are:
I had to fabricate the new throttle cable.
It needed a fuel pressure regulator.

 

[Bondo]

I had all of these ideas in my head as to what was going on with the starter. Fresh machine work, higher compression, either way the new starter is great!

So far no problems, I honestly don't know much about tuning these carbs. Worked with Holley's all my life. I followed the idle tuning that came with the instructions. It seems to have plenty of power throughout the power range. Still looking into a surge or poping at high rpm but I'm not willing to stay there long right now. The only problems I ran into with the new carb are:
I had to fabricate the new throttle cable.
It needed a fuel pressure regulator.

Ayuh,..... Ya need more fuel at high rpms, so I'd try smaller needles,....

Needles are easy to change, verses changin' the jets,...