1995 Scrab 29 w/single MPI 502 Merc. ported AFR Alum. Heads and 1:8 roller rocker per the ad was refreshed last season (mods added at same time). The exhaust is captains call and I'm told by the owner the ECU hasn't been reprogrammed for the modifications as he was told by his mechanic doing the work it's not needed with the OE exhaust. The boat hasn't been run until my marine surveyor did so today and per the tach. the engine would only achieve 3700 rpm. The prop. is a 23p and OE Bravo I drive, from what I've read the engine should achieve max rpm ~4800 with said combo.

So is a re-tune needed for the motor mods?

Is the prop. holding back from taching out?

Would old fuel hold it back that much?

My next step would be a compression/leakdown test, and fuel testing at the owners expense to prove the health of the motor. If he doesn't accept I guess I'm out the survey fee but oh well it served its purpose. If he does and finds the motor is ill I'd ask for $6k off an already very low list price which I doubt he'd accept and rather find someone who'll forego inspection etc.

Opinions please, thanks!

What specific prop is it, not just 23 pitch? Max rpm should be near minimum for a 502 MPI, but it has been molested, so what else may have been changed and possibly messed up?

Who did the motor work? I would talk to them and get a feel before you make a move. Bad fuel could have an effect, but..............

Bad fuel can be a huge problem. If the fuel is a year or more old the engine should not have run on it. Depending on how hard the surveyor tried to get it to run better it could have done damage. If an engine doesn't want to run DON'T force it. Find out what is wrong.
Doing those engine mods without changing the exhaust was a BIG waste of $.

Was cam changed too at same time? There is NO way the tune is anywhere close even with stock exhaust. I did a back and forth mail order tune for onesickpantera when he freshened his hp 500, he kept the original innovation cam that came with it and stock heads/stock exhaust but he had JimV bowl blend/pocket port the heads. He installed a o2 meter and drove the boat, wrote down what afrs it was showing. He went lean on the top into the 14/15-1 afr range from just porting the stock heads, at about 3600 it wasnt quite right, by 4000/4200 it was lean in the 14's, by 4500 it would have blown up if held above there. I tuned a spare mefi 3 ecu with a copy of his original tune and added 15-20+% fuel on the top. There is no way with afr heads that it isnt into the 15's, STOCK EXHAUST ISNT that restrictive (he had better exhaust but still). I will bet money it went lean on the top, surprised it wasnt lean popping. IF motors not hurt it just needs to be tuned correctly most likely and should be much closer to 5000 then 4800, should be banging the rev limiter at 5250 or wherever it is set at, fwiw, Smitty

Always some great answers on OSO. I'd let this thread run for two days then show it to the vendor.

Some things may ring true with him, tell him if he knows what's wrong, you may be interested if he fixes the problem. There's a chance he knows nothing and is just trying to unload the boat, he may know there's bigger problems and hopes to sell 'as is' or he may even be happy to fix a couple of things to get her running better and sell the boat in good faith.

Show him your survey, the opinions on here and give him the chance to fix things before making an offer. If he's not interested then either walk away or remember, 'buyer beware'.........!

RR

Great info. above and I appreciate it all. After emailing the seller he writes back, "I told you the engine needed refreshing." He sure didn't or I wouldn't have spent $550 on a survey as I'm not looking to purchase a vessel that needs immediate work, which he also knew. In fact his actual words were, "the engine were refreshed 2 seasons ago along with the upgrades and I don't know how many hours since; however, it hasn't been run this year." I'll be posting a buyer beware ad in the appropriate forum, for reference here it is as well. FYI the last sentence was added after I emailed him yesterday and noted the engine situation is probably a good detail to put in the ad.

I will provide the marine survey I had conducted at half my cost if anyone is interested in purchasing the vessel.


http://www.boattrader.com/listing/19...arab-30-660403

best $550 you've spent... better to have done that and walked then buy someone elses headache. good luck in your search.

Thats funny. He wants to "avoid confusion" but has 2 different prices posted in the ad, calls a 29 a 30, and it, the "30" has a "freshly serviced" engine that needs to be rebuilt Clear as day!

Good looking Scarab. If in the condition as pics show i would pay 15k shipped to me.

As pissed as I was originally and after seeing what is out there; I'm actually leaning back toward this boat. I just reviewed the actual survey yesterday and in addition to the engine health issue, here's what else came up:

1. No downward slope to exhaust, surveyor recommends higher risers.

2. Oily residue in bilge, needs thorough cleaning.

3. Relocate stereo amp and 110v outlet outside engine room.

4. Speedo Inop.

5. Broken Starboard rear vent grill

6. Cabin headliner needs restoration due to sagging & stains.

7. Hatch cover dog missing leaving open hole in hatch cover.

8. IMO heavy cosmetic damage to the port-aft corner which the surveyor sounded and says is fine. I'm not leaving it that way.

Additional pics. of the condition here https://www.dropbox.com/sh/cgs3sx34q...A8xubIa?oref=e


I'm on the fence whether to refresh the current long block containing the AFR heads and have to mess with tuning etc. Or to just drop in a Reman 502 and be done with it.
Here's the heads http://www.summitracing.com/parts/afr-2101-1 w/BBC Ex. Valve Option and Flat Mill Option. Are they worth re-using on an OE bottom end?


After seeing the full story above and knowing what's needed what's a fair offer to make? Thanks!