I have a new update on Party Gras, I took it out yesterday & my water pressure lines are plugged up with the fine silt that is in the water so I need to find a different place for that. But on the down side I have a oil pressure problem that starts @ 5000rpm. The boat runs & cruises fine, a little slow out of the hole but nothing to cry about. My oil pressure on the port engine runs40-50psi cruising, yesterday I pushed the sticks forward to 5000rpm & the port gauge dropped to around 15-20psi & was fluctuating rapidly. Pull back the stick & it jumps right back up to 45psi steady. I did this three times shortly & the exact same thing happened, back to the trailer. No odd noises everything tight all connections good, no oil loss or oily smell. Plan on installing a manual gauge with a t to verify oil pressure and verify gauge. I can also jump the wires to see if the gauge changes with the other engine. A friend suggested a restrictor failed & is pumping too much oil to the top of the engine, don't know but why would it only do it @5K &go back to normal once slowed down & right back to the same once 5K again. Any Ideas? I'm hoping it is something simple but right now I am at a loss. Could use some help if anyone has experienced this problem before. Thanks in advance, Randy

Sending unit?

Gonna install a manual gauge tomorrow & see how things go. Talked with the builder today & he seems to think the sending unit went out & also had me check the oil level which is a punch mark on the stick above the full mark. Both are full to the punch mark. I really hope it's something simple. I am also going to change the oil tomorrow, cut the filters open & see if anything bad is lying around in there. If all is well after that then I can address the prop slip issue of 22.9% If I can get it down to around 10% the boat should do close to if not over 90mph. I will be wishing for some luck in this department as a lot has happened in the last couple of weeks & months. I will post my results. Randy

Randy.. Been following the thread.. VERY well put together. Thank you for sharing, I can't wait for you to get your 90... That would be some real fireworks on the 4th of July. Best of luck.

Thanks o2bafloat, everything that has been done under the bonnet I pretty much learned from people on this website doing similar work on their own boats so I need to give some thanks to a bunch of people who have shared their work here. Without the people here who give their experience & knowledge to others I never would have attempted a project like this. Randy

Your oil pan is running out of oil at higher rpm. What kind of pans do you have?

Sending Unit, too much oil and getting aerated or not enough oil.

If the water psi hoses are in the block drains, the will constantly plug on the river.
What I did to help was to drill out the inner hose fitting so the hose would through it and into the block an inch or so. It still clogged once in a while. That was on my Pantera.
On my AT, the fittings are in the intake and they have never clogged.

Peyton, Black Baja, Griff, I think my oil problem is indeed a sender problem. After changing oil & filter, cutting open the old filter & finding nothing bad in there,( there was a minute amount of powdery stuff in both filters) I installed my manual gauges in both engines & they both ran 65-70psi @ idle til warm. I used a infrared gun on the filter to determine temp, @150 degrees they read 50-55psi @ idle. At 3-4-5000rpm they were both @60psi & steady while electric gauges read lower & fluctuating some. Griff, I have a spare fitting on the intake to mount my pressure gauges to so I hope that cures that. The 4th was a fun day with the wife & friends,and the grandson even brought the puppy dog. He graduated to big boy boats today. I have new sending units ordered so I hope that cures the problem. Thanks for your responses, I'm glad it wasn't anything serious. Randy

Well I replaced the oil senders in both engines, they both read close to equal but approximately 20 psi lower than my manual gauges. I guess I should call Livorsi & see if there is a resistor to put in line to make them more accurate, at least I know there is 20 psi even if the gauges are close to 0. I said earlier in this thread if I have any problems with my mounts I would give Sam (The Deep) first dibs on telling me "I told you so". I was looking things over last night & saw the mount nuts had worked loose, Sooo I pulled the drives, checked the alignment, still good, so I cranked the nuts down & did what I should have done and double nutted all 4. I also found a small oil leak, it feels like a fitting down at the block adapter so I will have to get a mirror down there for a better look. I have a friend that wants to try my shorties & he has stock length XRs so I think that is next to figure out my slippage issue, he also has some 30p 5 blade hydromotive (I think that's the name) props to try so stay tuned to my adventure in trying to find the big 90. Randy

Randy--- black baja could be right
I've had the same oil issue--- builder used stock pan and hv pump drained oil out of pan until it was sucking air. Then it blew a filter line rated for 2500 psi and by the time I got it shut down spun a bearing
Not sure what size pans you have but make sure they are big!

When I bought my boat it had the same oil pressure dropping problem. Turns out there were no windage trays in the oil pans. Eventually I figured out it was windage because when it would happen there would be a burnt oil smell, probably from oil hitting the pistons excessively. I did wipe out my main bearings in one engine before concluding what the problem was so make sure you're not testing this theory too much before you do something.

I recommend using a MasterLube accumulator/pre-oiler. I have one on my boat and use it to pre-oil the motor before starting, and as an accumulator when running hard or in rough water. Very cheap insurance.

Are you sure you have the correct senders???? The Merc senders are made for the standard sweep 0-80psi gauge. If your gauges are different, you may need a different ohm sender.

Griff, the senders I installed are BWD 80psi senders, I ohm checked them & they read almost identical as compared to the sierra ones I also bought which did not. I was more concerned that they read the same so I can narrow things down to wiring or gauge. I really don't want to pay mercs prices if I don't have to. I am a lot more comfortable after running the boat with both electric & manual gauges at the same time, at least they aren't bouncing around & the engines aren't starving for oil. My gremlins are manageable & I physically know whats going on so I am less worried about it. Now I have to find my small oil leak & get that fixed then I can continue with dialing the boat in. Randy

I hope you get it figured out randy, I know I'm tired of working the gremlins out of mine , kill them 1 step at a time

I got the header off & stuff out of the way, not quite sure if the adaptor oring is leaking or the an fitting so I need to pull the adaptor off. That will be tomorrows project. Woo Hoo. At least it isn't anything broken. Randy

Lucky you, I've been fixing my own screw ups

Depending on what Livorsi/Gaffrig gauges you have, you may need to get senders from them.
Also, don't use sealer on the sender threads. It prevents it from grounding properly.

CP Performance owes me some money so I talked to Mike & he is sending me 2 oil pressure senders & 2 water temp senders. I will see if that cures my gauge gremlins. When it cools down a little I will pull my oil filter adapters, have 2 new ones on the way. If all goes well with that all I need to tweak inside the boat is the water pressure sender location then I should be free to continue dialing in the drives & props. Randy

Well guys I'm back again, I replaced my oil filter adapters, no more leaks. I replaced the block plugs with the older merc brass ones, where the water pressure fittings were I put T fittings in with the pressure tap facing up. Reinstalled my oil temp senders, changed out my -2 inch sportmasters with stock length XRs, installed some 30p 5 blade Hydromotive props & went out to play. The water pressure gauges work like their supposed to, my oil temp is about 190 @ cruise up to 220 @ full throttle. I noticed a top temp of 250 when I held it open but temp went right back to 190 after slowing down. The boat came up on plane much better but 5 blades is still too much prop. 83mph @5000 with 1.50 ratio & 30p 5 blades. Works out to 12.39 or so prop slip, much better. I have some 30p 4 blade bravo 1s to try, not sure what they will do I'm guessing I'll pick up 200 or so rpms, I would like to be at 5400 if anyone has any suggestions I'm all ears. Randy

I would guess you will pick up close to 500rpms going from 30" 5 blades to 30 Bravo 1's. Slip % will also go up.
Did the new oil psi senders give you accurate readings????

Griff, I haven't received the Livorsi senders yet they should get here Tuesday or Wednesday. As far as props I will try these out then I have a good baseline to go by. Randy

Well I think it's time to get the prop guru's involved, I started with -2" storties with a 1" spacer and 32p bravo 1s. 82mph @ 5200rpm. 22% slip. Boat felt kind of loose but still very much in control. Changed out the lowers to stock length XRs with 30p 5 blades. 83mph @ 5000rpm 13% slip. Boat felt much more planted & stable. Today same stock length lowers 30p bravo 1s 83mph @ 54-5500rpms 19% slip. Boat felt kind of loose again same as with the 32s. My thoughts after this test, Just for grins & while I have them I think I will re try the 32s with the longer lowers just to see but I will talk to Brett & see what he recommends. I have not tried swapping the prop direction as I have no idea what that will do with this hull. I like the maneuverability of the 5 blades but at the same time I don't want to be any harder on the drives than I already am with this power. Any suggestions? Randy

Randy whatever happened with this

Randy great work. I recently became a member and reading through the rebuilds ion OSO is amazing. Don't think I could tackle a project like this. Good luck.

Welcome ChrisL, stimleck, I have been running different props & settled on the 30p Bravo1s for now. After breaking the engines in & dealing with a couple of pesky gremlins I went boating all summer, made lots of noise & burned a lot of gas. I went from 68mph up river & 70 down to 84 & 86 up & down. Overall I am pretty happy with the results, I think there is a little left on the table prop wise but I'm not sure I want to spend money on labbing the props for the river. ChrisL all I really did with this boat was clean up the engine compartment & a repower, that's not too tough. There are people that are doing some really cool stuff on here & are very open and free with their knowledge so if you want to do something to yours all you gotta do is ask. Randy PS if I could figure out how to load a video on here I have a couple of fly bys @ 80+

http://www.youtube.com/watch?feature=player_detailpage&v=JErylDSJ-ik

[ATTACH=CONFIG]522170[/ATTACH][ATTACH=CONFIG]522171[/ATTACH][ATTACH=CONFIG]522172[/ATTACH][ATTACH=CONFIG]522173[/ATTACH] A few updates for this year, The coolers were not cooling enough on hard runs & too cold while idling around. New finned 420 valve covers & some Eddie Marine flame arrestors. I think with the headers mounted it is going to look great. Randy