Offshoreonly.com - Well, that's disappointing

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Quote:

Originally Posted by SABER28 (Post 4807295)

how many batteries does this boat need?

Good catch. Lol.
Must be a party boat. :thumbs

I should get a better pic for you guys of the engine bay. I really do have a lot of room inside there. Getting to the bottom end is a ***** because of the stringers ad the motor mounts, but the top end is really not a problem .I can stand or kneel on both sides of the engine with no problem.

I was wondering if I should remove the top end and inspect before removing the engine. If piston damage is observed, then it's obvious it needs to come out. Funny how most say no and a few say go for it. I guess that's normal for the internet.

I'm going to call the mechanic tomorrow and see what his schedule looks like. If he can't get to me until winterizing boats is done, it may take a while. But in all honesty, I'm not going to need the boat for at least 6-7 months. (dam you year-round boaters have the life) I'm also waiting to speak with the engine builder and see what input he has, and what his schedule looks like.

Deep down, I know the bottom end needs to be inspected. Just for piece of mind as someone stated. But I'm not looking forward to the additional costs.

It really does suck to know it cost a lot of $$ to get this engine and get it running properly, and now it crapped out in just 30-40 hours on me. :(

I knew the down side of the additional maintenance with this, but was told the engine had around 200 hours and the springs were already replaced. Pretty sure that was full of ****. I'll be finding out real soon.

Thanks for the advice gents.

Has anyone determined exactly what the difference in HP is between the HP 500 carb (470 hp) and the 502 MAG EFI (415 hp) is? Are both those figures taken at the prop? In all honesty, I was hoping I would be able to turn a slightly bigger prop and gain 3-5 MPH over the 502 Mag. What I was told, was this particular engine made 529 hp on the dyno with the MSD distributor, QFT 850 carb and the CMI E top headers. (beginning to doubt that claim too)

F2, my battery boxes are about 1/4" away from the exhaust. Not touching, but darn close.

Quote:

Originally Posted by SABER28 (Post 4807295)

how many batteries does this boat need?

Quote:

Originally Posted by SB (Post 4807297)

Good catch. Lol.
Must be a party boat. :thumbs

2 for the engine and 2 for the stereo

I can always add 1 for the engine into the stereo bank if need be.

I call it the party barge.

(4) amplifiers
(8) 6.5" speakers
(4) 8.8" speakers
(2) 12" subwoofers .

Blue LED lights in the speakers and throughout.

https://cimg6.ibsrv.net/gimg/www.off...c3e761c652.jpg
https://cimg9.ibsrv.net/gimg/www.off...27f84d3db2.jpg
https://cimg2.ibsrv.net/gimg/www.off...149a107761.jpg
https://cimg3.ibsrv.net/gimg/www.off...a3d2a2563c.jpg
https://cimg4.ibsrv.net/gimg/www.off...ae07bc5c75.jpg
https://cimg5.ibsrv.net/gimg/www.off...9db16b8763.jpg

The HP500 is advertised making 500 at the flywheel and 470 at the prop through a Bravo drive. The 502 MPI makes 415 or so at the flywheel and about 380-385 at the prop. Engine and drive condition, humidity and temperature, and load all affect the numbers.

Nice sound system!

I have a nice sound system in my Mustang convertible. It's amazing how much current those amps draw while running on only 12 volts. Sometimes I wonder if a power inverter and 120v amps would work better. Good luck getting your problem sorted out. Once the batteries and exhaust are out of the way you will have plenty of room to work on the top end.

OP where are you located ? did you buy the new engine from a member here

Quote:

Originally Posted by xlint89 (Post 4807298)

Funny how most say no and a few say go for it. I guess that's normal for the internet.

As always, different strokes for different folks.

Cannon plug, drive, front and rear mount bolts, exhaust couplers, fuel hose, battery lead to starter, and a few ancillary wires here and there.
Then it's pulled. You or your mechanic can work on it in a Lazy Boy next to the toolbox.

I'LL take that any day versus climbing in and out of the boat 50 times, lying on your head, bent 50 ways and whatever else.
Not to mention no major grease and oil mess in the bilge.

I'm all for pulling the heads in the boat if you have the room. You say the leak down test had air coming out the carb. Seems more valve related than piston anyways. You would probably not be able to see a bad piston or leaky ring and probably just leaky valves. I say pull the heads in the boat. Use the extra labor cost to pull the engine to dump into porting the heads, adding better valves, or rocker arms...you get the idea.

Quote:

Originally Posted by xlint89 (Post 4807089)

I removed a 502 mag EFI and replaced it with a used HP 500 carb engine in my Cobalt 252.

https://cimg2.ibsrv.net/gimg/www.off...f5e4990330.jpg

A lot of you read about the number of issues I had to iron out after the install. Finally got everything squared away with the help I received from this forum. (Thanks again) Was actually enjoying the boat and managed to get about 30-40 hours on it this season.

The stock prop was a Mirage plus 23p that turned 5200 RPM at 63 MPH with the 502 mag. The new to me engine turned that prop at 5200 RPM at 63 MPH with a full load of adults. Got up on plane quite easily and has a nice midrange "hit"

Threw on a Bravo I 24p prop and turned 5200 RPM right around 62 MPH and planes pretty fast. Is also pretty responsive to throttle control. I like the Bravo I.

Looking for more top speed I installed a new Mirage plus 25p. Only turned about 4800 RPM at 62 MPH. Plane was not as good as the 4 blade, and not quite as responsive.

Hoping to gain the plane and responsiveness back I tried a Bravo I 26p. Only turned around 4500 RPM at 60 MPH. Still planes out pretty good and responsive.

After spending the $$ to buy this engine, then iron out all the wrinkles of the swap, I'm not even able to turn a larger prop than the engine I replaced. Pretty frustrating.

Hoping there might be something wrong, I did a compression test and found 2 cyls low. 1 on each bank.

https://cimg4.ibsrv.net/gimg/www.off...046fcc78d3.jpg

Ended up taking the boat out after doing the compression test and replacing the spark plugs. It ran fine for that outing.

https://cimg6.ibsrv.net/gimg/www.off...9bb44105f1.jpg
https://cimg8.ibsrv.net/gimg/www.off...5341515dcf.jpg
https://cimg1.ibsrv.net/gimg/www.off...b527e2ebec.jpg

Loaded it up on the trailer and the engine didn't sound right when pulling it up on the trailer. Even the GF noticed it sounded weird.

Bought a leak down tester today and attempted to test the 2 low cyls. I was getting almost 80% leakage and could hear air coming out the carb. Figured I did something wrong with the test. Not at TDC or something like that. Figured screw it, fire it up and see what happens.

Ran for about 4 seconds and made such a clatter. Clicking, tapping, knocking sounds from the top end.

So.... With this being a used engine with no real history on it. It being a HP 500 carb with known valve spring issues. And a cam that is notorious for sucking water at low RPM.

Do I yank the engine out? Going to be difficult this time of year as my mechanic will most likely be busy with winterizing.

Or do I remove the heads while in the boat and see what I'm dealing with here?

There's quite a bit of room to work inside the engine bay, so top end wouldn't be too difficult to do. If I were to address the cam, it would definitely need to come out.

Not quite sure what to do? Any insight would be appreciated.

How many hours are on the engine? Top end is the weak link, bottom end is good. The valve springs break and then the valves hit the pistons. Hopefully its just a head problem.

Quote:

Originally Posted by TomZ (Post 4807303)

Thank you. So approx 100 HP difference, Should be able to turn a bigger prop and about the 3-5 MPH I was expecting. Thanks for that.

Quote:

Originally Posted by F-2 Speedy (Post 4807326)

OP where are you located ? did you buy the new engine from a member here

Cleveland. Yes, it was listed in the classifieds.

Quote:

Originally Posted by zfrilly (Post 4807381)

The leak down test was almost 80%. It was after that I started it up and it ticked and clattered immediately, so I shut here down. Hoping I didn't damage the pistons or heads by them making contact.

Quote:

Originally Posted by jeffswav (Post 4807386)

How many hours are on the engine? Top end is the weak link, bottom end is good. The valve springs break and then the valves hit the pistons. Hopefully its just a head problem.

This is what I was sent. The motor has approx 180 hrs. Underwent a full rebuild done by Chief before he bought it. (He has receipts, I never saw or got them) New heads, springs, cam, carb etc...

So with hind sight and reading between the lines, I do not know how many hours. Because I had to replace the carb and when I questioned him about it, he said it was not the stock carb, so that is what he meant by new. The engine came without an exhaust and I thought there seemed to be quite a bit of rust/scale build up inside the exhaust ports for having new heads. He listed a cam, but sent the specs of a stock HP 500 cam. Why would you install a new stock cam that has reversion issues instead of one with more lobe separation? So I'm highly suspect of any internal work that I cannot verify.

I do wish it was just the top end and I could get a set of performance heads to remedy this. I could leave the engine in the boat and would prob get away fairly cheap compared to a complete rebuild. But I have a feeling I should have the entire engine looked over.

Didn't speak to the mechanic that would remove the engine, but his wife did tell me they are in full swing with winterizing now. I will most likely need to wait until winterizing has died down.

Still need to talk to engine builder and see what his schedule looks like as well.

So trying to coordinate yanking the engine, getting it serviced, engine put back in, and getting the boat put up for winter and into storage. Sheesh..