Oh-no Drive issues
 

3rd time out with new to me 272 w/502, lake was glass may have pushed it too hard? Bought boat, 63mph GPS with 2 cornfed sellers, me and the girlfriend on test drive. Got it home, cleaned it up, new fluids, new cap rotor,wires and plugs(one plug had no electrode). Descaled the nasty prop(15 x24 4 blade unknown manufacture). Was hoping for grandeur, first 2 outings water was rough and I was getting used to the ole girl, now the conditions were optimum. 66mph (gps) trimmed out, 4600 RPM, engine sounded fantastic- it has some real nice stainless headers. 2 times the boat just bogged down trying to get up on plane and nearly died. shifting into neutral and letting the engine cough and sputter till it cleared up(bout 30 seconds) then when engine was revving clean and crisp I would shift it into gear and it would not want to go like linkage was binding or something, when it went into gear it did not want to come out. Had to shut off engine force the lever to middle(neutral safety) position, start boat, then it would shift in and out and reverse smoothly. Headed back in when it happened the second time, went to trailer the boat and the shifter stuck in forward. repeated the procedure and it shifted fine again. Drive is factory Bravo 0ne 1.5, it has a Hardin Marine external steering set up (single cylinder). Worried. Hoping it is something common that you guys may have heard of. Please have some good news for me. A little background on me- diesel mechanic currently working at a Kubota dealership. Never cracked into an outdrive, but not afraid to get on in there. Just would rather wait till Winter time. Plus, funds are a bit low after this purchase.

How high were the rpms when you tried to shift?? and shifting a bravo when its not running is not good for it...

Shifting was only done/attempted at idle. Good to know on the not running shifting, thanks.

Pressure test your headers. It sounds to me like they are leaking water into the engine.
Your RPM should be at 5200 trimmed out at full throttle.

There was no sign of water in the oil when I changed it, dont know if there would be from leaky headers. They do not look fun to remove, any way to test on the motor? I felt the same on the RPM, but on the prop slip calc, it was at 8%. I thought maybe that big 15 and ?/8" 4 blade may be too big for the boat? Was planning on getting everything all squared away and trying a different prop. The engine, even with the fresh tune up, is still hard to start sometimes. Not something I expected from the fuel injection. My quadrajet 330hp always fired up instantly. The 24" pitch is even hooking up too well at idle, very hard to park boat and true "no wake" is not possible without going in and out of neutral. I am sure most of it is the novice operator.

Just popped that in the calc at 10% I would still be over 70, That is what I was hoping for after the tune up, figured 63 with 500 extra pounds a scaly prop and only hittin on 7 cylinders, 70 was in the realm of possibility.

Yes. It was black, but no metal in the oil or on the drain/vent plugs

Which you shouldn't expect. Something is wrong. let's take a fuel psi test and report back. if you do not have a fuel psi tester they are cheap, or cheaper yet, AutoZone has free rental tools. Is this a 502 MPI ? Cool fuel or VST ? Serial # ? Very typical for rubber vac hose to fuel psi regulator to be off or cracked....even if 10-15 yrs ago it was typical. LOL.

Yep filled from the bottom, after letting it drain overnight. removed and cleaned out the reservoir. It is a 1995 MPI. Smells very rich. I am fine with upper 60's for now. Just want it to start and shift and be reliable lol.

Got a tester at work (0-100psi ok?) Not sure what you mean by cool or VST . The engine serial number is OF533769. Regulator is in the back I think, yay I get to pull the engine cover again( kinda sucks doing it by yourself). I will try to remember to bring home that gauge today. Big problem is I have no way to run it out of the water. I found those "muffs" to be worthless and cost me a brand new impeller on my other boat (330hp bravo 1 ). I rigged up a valve so I could hook a hose directly to the intake line and shut off the drive pick up. Great for winterizing it too. May have to order parts to do this one. Would love to hear about how any of you guys run your boats out of the water.

OF593772 is the engine serial number whoops. The hatch is electric, but when open, it blocks access to the regulator and distributor(thats why I had to pull it when I did the tune up). Wish there was a definitive way to tell if headers are leaking without pulling them off the engine/boat. I heard the lobe separation angle is small on marine cams to prevent reversion, so once it is running water is not likely entering. But if I marked the balancer and pulled the plugs out of the cylinders that had open exhaust valves after shut down, maybe?

Remove the Outputwaterhose from Header and close this side, and build somesthing to give pressure on the input side!
When there is a hole in the header,the pressure will allways gone!
Michael

I think my headers may be different, than ones you speak of, but maybe I could remove the straight pipe and cap the collector?

I got the pressure tester, and a buddy coming over to help remove the cover. So, what am I testing?

could have a dead cylinder..you mentioned that one plug was missing an electrode? I would start with a compression and spark test and co from there...may have a bad head gasket causing low compression...once you get the running issues sorted out I would move back to the drive issue...I'm betting that is a bad intermediate shift cable...shifting them with the engine off can stretch those...I would also look at the shift cavity for evidence of water which could be a sign of the back cover leaking...this will cause the detent ball to rust a seize...mine had similar issues shifting when I got it and it ended up being that whoever put the drive on last didn't hook up the shift cable correctly to the drive and just crammed it on causing it to get stuck in gear....but like I said I would start with the engine issues first...one problem at a time...that thing should start just like a modern car and sit there and idle.

Well, lake season is over here, winterized the boat. Had 6 ppl, fuel and beer and trimmed out at 65mph(GPS). This may not sound too impressive, but I am super excited for next year. Since muffs have never worked for me, I had to go at winterizing by draining everything. Since I was all wadded up in there any way, I did a compression test as suggested. All summer I always crossed my fingers everytime I shut it off, hoping it would start again. Some super stressful moments, but she always busted off eventually.
135-141 on cylinders 1-6. 7 was dead, yep 0psi, and 8 struggled to get 10psi. I am thinking leaking headers and 2 bent rods. Least I made it till off season. Question is where are the headers leaking? is it possible it is just at the collector gaskets/seals ? They were leaking black sooty water all over the engine and cover/hood when I first bought it. I tightened the clamps and is stopped spitting water everywhere, but there was still sooty residue after every outing. I want to run headers, I dont want to bend anymore rods. I hate to plop down cash on new headers if new gaskets is all I need. I know nothing of these marine headers, I have read a bunch on the forums about how hated they seem to be- and understandably so. If any one knows how to tell where a leak is, please let me know. Also would love to hear suggestions on a rebuild, any special components needed? I have heard about cams, and something about rings and head gaskets. is this stuff absolutely necessary? If the engine has a roller cam, can I put a cam for a 525 in its place? I want to stick with a marine grind for sure. Also thinking of losing 100lbs, and going with aluminum heads- any down side there? All of the plugs were sooted rich, so there is definitely a problem with the fuel system as well. Since I know nothing about this MPI setup, I am thinking of shelving it, till I can afford a procharger and figure how to tune it some day. May go with a good intake and a huge spreadbore Holley. Noticed they sell "marine" intakes as well, anyone no why I couldn't run an automotive version that's 200 bucks cheaper? Obviously the excitement is not from the cubic dollars I am gonna be forced to spend, but from seeing the results 2 more contributing cylinders are gonna net.

Post a pic of what headers you have. You are going to need to pull the engine. Pressure test the headers with them removed from engine.
I doubt you have bent rods. No way it would keep running without blowing up. More likely to have holes in pistons or valves burned or stuck.

I think they are Custom Marine, I will get a pic when I go out next weekend(gonna get cold all week I hear). We get bent rods a lot at work so that was the first thing I thought of.

A Baja is usually in the realm of 12-13% slip unless you have BBlades tweak the prop a little.

Also, I would think 70 is really hauling the mail in a 272 with that power. I would assume high 60's. What does everybody else think?

Im thinking blowen Head gasket, and #7 piston will have chunk out of it in the valve relief that is cut into the piston. Pull it and rebuild it.

Once you determine whose headers you have, check the manufacturer to see what they charge to do a pressure test and inspection. I have Lightning headers and sent them in and had them tested. For the piece of mind it was well worth the money, I think it was $150 including return shipping. To get 0psi you have more than a blown gasket you may have a stuck valve. Based on how rich it's running that's probably the issue, too much carbon build up. If you bent a rod from a hydro lock you would still see some compression or it would have let loose. As far as the intake, depends on your water. I have aluminum heads and intake and after 10 years both are still mint. But I boat in really really clean water. I'd pull a head and see what you have for sure, you may get away with a valve job. I see lots of complaints of the MPI systems running rich. There are some good tuners on here, see what they can do for you. As much as I like EFI on my cars and due some of my own tweaking, I really like my carb on the boat. I once ran the batteries dead on my boat and it would only turn over one compression stroke. I still got it to start, try doing that with EFI.

I will post detailed pics of the autopsy, I am still leaning in the bent rod direction, we should start a poll? Lol. My reasoning, and I have no experience with marine engines, is no water/gas in the oil, no popping out the pipes or the flame arrestor. It never ran hot. The boat did a GPS'd run at 65 hitting on 6 so the 2 "dead" cylinders are at least working enough that they are not causing parasitic drag on the motor- they are paying their own way lol. Cant wait to find out.

I am not thrilled with the lack of an interface to see whats going on, and having to spend 500 or so and send it off and wait to have it "tuned". I have been tuning carbed engines since I was 14, very comfortable with it. The "bolt on" Procharger is the only advantage I see to keeping the MPI and with the cost of this rebuild it will be another year or so till I can afford one. I built a dyno'ed 638hp 427bbc naturally aspirated for my Chevelle, Pretty sure I could get real close to that with a 508 even within the confines of "marine" specs. The CR would likely be too high to run a supercharger, so I would have to make the decision at the time of the rebuild. High tech(1995 lol) supercharged cool factor or good ole brute "old school". Hmmm. Guess it will depend on how bad the damage is. One thing I want after this summer, is reliable starting/idling.

Looks nice, does it plug directly into the mercruiser MPI distributor? I think your boat has a bit faster hull design than mine, but a reliable starting, excellent sounding 75mph boat would make me very happy.

I've hydrolocked a cylinder before to where it bent a rod but the boat still ran. It shortens the rod enough to where the underside of the piston hits the counterweight on the crankshaft and makes one hell of a knock. It will run but no way you are running the engine WOT for any amount of time before destroying the piston or beating the rod bearing out of it.

IF you check their install manual, you will find how to connect it to the Mercury distributor. I recommend disabling the mechanical advance and using the digital advance in the Daytona controller. I'm running an MSD distributor that is locked.

I will take your word for it, cause I have no experience with a boat engine. I have seen the skirt knocked off a piston with a bent rod and the engine still running, but unfortunately it did tear the the cylinder up due to the lack of piston support. Have never even seen a 502 piston so I dont know if they even have much of a skirt. What else could cause low compression on only the two rear cylinders? I could do a leak down, but why bother, it is coming out no matter what. I hear 400 hours is pretty much time for an overhaul anyway? Boat has 392hrs. I had the boat out several times but actually only put 9 hrs on the engine. I bought it (unknowingly) in this condition, so when whatever happened it could have made a racket.

Cool. I have an MSD distibutor I could put in it, I was planning on a 6M box if I went carb.

K. Headers pulled. Pics taken, how do I post?

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Got it! Also took a pic of the fuel regulator set up, If I am going with the MPI, I will need help diagnosing why it is running so rich.

Getting Late(dark) here I was going to pull the drive today, but it will have to wait till next weekend. It's dark when I leave for work and dark when I get home. Might get ambitious and get the engine out and on the stand too. So I capped the collector end water outlet with my hand and blew into the rubber water inlet. Starboard side held, port side was definitely not holding. I know its not a real test, but it doesn't seem good. Wondering how the "send it in and have it tested" thing works, if one side is for sure not holding pressure, should i just order a new set and save the 150? Or do they apply the 150 toward a new set? If there is any chance they could be saved it would sure help with the repair cost of this engine job.

Number 7 and 8( back cylinders one on each bank). If both head gaskets are blown, they are blown into water jackets, as there is no external signs. I would think there would be some water in the oil. We will find out soon. Gosh I hope the block is ok...