Picco P90 Blue Head-run with fuel pump?

Hi I bought a used never ran Dumas 55" Wellington Scarab hull kit with all the railing and vent options. It came with a new Picco P90 Blue head engine never ran. I have most everything for the boat except engine mounts which I am sourcing a CNC set but my question is the tuned pipe with the engine set up has no exhaust nipple installed for fuel pressure to the carb? I found a set of instructions in the boat for a VP fuel pump but no fuel pump with the boat yet on the side of the crankcase is the pressure port for a fuel pump. I am guessing the VP pump instructions which are old are the same VP-30 Perry fuel pump I have new to install? I do not know if the crankcase nipple or port if this is original from Picco or added for the pump? I wanted to install a Perry/Conley fuel pump which I bought but am not sure if the Picco carburetor will work with a fuel pump? I can't tell if it is a air bleed type that I am warned that my fuel pump will not work with by the Fuel pump Perry instructions? It seems to me the Previous Owner knew what he was doing since the boat came with everything else and has two fuel tanks a large one and a small 3 oz one in line so not wanting to screw this engine up being new old looking for advice or knowledge of these engines. Bought through a third party the Hobby Shop not able to talk to the original owner.

Also what percentage of nitro is recommended for a Picco P90? 30% ok? I have the original engine box but no instructions with it for break in or type of fuel to use. Having probably 15 nitro R/C airplanes I am familiar with nitro engines but parts and info for this marine engine seem to be rare. Any help surely appreciated. Thanks Ken

Here are some pictures of the Picco P 90. Hope someone can give me some answers on fuel recommendations and break in procedures and wether a VP-30 fuel pump will work with this carburetor. Thanks.

Take the fitting out of the crankcase and plug and use a fitting on the widest part of the pipe and run line to tank for pressure.

Brad

I made the mistake of trying 55% nitro on a Picco 90 Blue many years ago and burned a hole clean though the top of the piston. It was running a little on the lean side. Since then I never ran any higher than 40% nitro with a minimum of 20% oil rating. I was running 20% oil or more when I fried the piston.

Some people get ride of the fuel pump and make a thin medal plate to cover up the opening on the engine case.

The pressure tap on the crankcase can be used to pressurize the fuel tank, same as a fitting in the pipe would. Standard procedure on engines with an exhaust throttle where pipe pressure is affected when the exhaust throttle is closed. Or remove the pressure fitting from the crankcase, plug it with a proper sized screw & drill & tap the pipe as mentioned before & install the fitting in the pipe. No pump needed (-; Only downside to using the fitting as installed now is pressure would be affected with carb opening & closing. That style is better suited for use with a fixed venturi, not a carb. Put it in the pipe for best results.

That motor is not a P-90, It is a H-90 (Hydro 90) with a head someone has painted blue. The last model of Picco 90's were called Bluehead 90's and had a factory fuel pump mounted on the side of the crankcase above the carb. Your pictures helped show what model this one really is. The hydro 90's came with a needle bearing rod and instructions to change it out to an RPM rod. People who ran the stock needle bearing rod were treated to a crankshaft pin that looked like a squirrel chewed on it. Later the Picco Hydro90 was shipped with a New RPM rod included in the box. If it was mine I would not run it with out changing the rod.

Wow...Wealth of information! Thank you for the replies. So now I need to get this all straight. Remove the nipple and drill and tap the widest part of my tuned pipe for exhaust pressure to keep both fuel tanks pressure-no pump. Guess I wasted my money buying a pump. Same as a airplane and a Proboat 31 Thundercat I had owned before. Thank you for the replies I will do this. Now the scary part...RPM rod? Any way I could see if this has been done? If I remove the crankcase cover is there a difference that I would know if a RPM rod had been installed? Now the scary question if not which my bet is not....where in the world could I obtain one?

I am very mechanically inclined. I know there is 332 loose needle bearings in the Trans on a 1966 Jaguar E Type. I do all my own work so not to worried about my capabilities to replace the rod but to find parts... I have rebuilt several Saito 4 stroke airplane engines in the past. I also had a 55 inch 26cc gas boat and built a Dumas "Miss Thrifty" hull powered with a K&B .67. Sold all of them a couple years ago when Northern California Lakes dried up. But now getting lots of rain time for a boat again! Local Club pretty much defunct. Hobby shops around here not real R/C Boat friendly. I cannot find 30% Nitro Boat fuel anywhere only car fuel.

Thank you for the info and identifying the engine. I may now go ahead and polish the head up similar to another post on this Forum. I am just impressed with the looks of this engine. Looks to be a powerhouse of a motor if I don't blow it up. Ken

Also if it is a H-90 motor why is it stamped P-90 on the crank case? Not questioning in anyway the extensive knowledge here just curious since you obviously know about these Picco's. Thanks Ken

Rudy Formanek said:

That motor is not a P-90, It is a H-90 (Hydro 90) with a head someone has painted blue. The last model of Picco 90's were called Bluehead 90's and had a factory fuel pump mounted on the side of the crankcase above the carb. Your pictures helped show what model this one really is. The hydro 90's came with a needle bearing rod and instructions to change it out to an RPM rod. People who ran the stock needle bearing rod were treated to a crankshaft pin that looked like a squirrel chewed on it. Later the Picco BH90 was shipped with a New RPM rod included in the box. If it was mine I would not run it with out changing the rod.

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Also worth noting I am glad that the pump is not needed anyway and it runs the plumbing like a standard Nitro. I had a 8ft wingspan P-38 with twin Saito's. Problem was the tanks were set too far back exhaust pressure alone was not enough engines kept starving for fuel. Watching a P-38 have one the engines quit mid air would make my heart skip a beat since these Planes have a bad tendency to loop around on a engine failure. Anyway installed VP fuel pumps and if anything the engines ran worse or wouldn't even start. Tried another Brand fuel pumps that set me back couple hundred dollars and still same results . Simply a bad design on the fuel tank placement. So finally gave up and sold the plane. Never had much luck with fuel pumps.

I know this is a Boat Forum probably don't want to hear about Aircraft but felt it would help show some of my experience with Nitro engines for the last 25 years with them and that I do appreciate the advice just don't want to ruin the engine on something I do not know anything about Picco's. Ken

I for one have no issues hearing about an airplane, especially the "Twin Tailed Devil" one of my all time favorites! RPM (Richardson Precision Machine) has been closed for some time, but the rods do turn up from time to time. I'm not familiar with that Picco, so I have no idea what a stock rod looks like. The RPM rods are billet/machined & are generally finished better than stock rods. If you post a pic of the rod, I'm sure someone on here could identify it. Derret on here was the owner of RPM, try contacting him with a pic in a PM. I'm sure he could tell you if it is one of his. Also watch eBay & post a WTB ad in the for sale forum, you would be surprised what folks have stashed away. I was an auto tech for 40+ years, amazing what we have stashed away in the memory banks ain't it?

You could take off the backplate (rotor-plate), carb side. Carefully note the position of the disc and crankpin for reassembly. Should be able to tell if it has a steel needle bearing rod(stock) or an aluminum rod with a brass bushing RPM). You might be able to run the needle bearing motor on 15% nitro or less, just have had nobody that has done that, so really can't say if that works or not. The Picco H-90 was a powerhouse, so much so that it cracked the crankcases at the mounting lugs, on race fuel. If the cases had been stronger, it probably would have been allot more popular. Aeromarine used to sell aftermarket Drum valve intakes and aftermarket bar stock frontplates with a very unusual bearing set. Many were left scratching their heads when after the Hydro 90, Picco totally redesigned the 90 and came out with the Bluehead 90 and it was a complete DOG. Many felt they should have just beefed up the H-90 and it would have been a winner. Should be mentioned that they never seemed to be able to make a conrod that would satisfy the American market until the Blackhead 45EXR LS. (2008??) Kudos to you for posting pictures or we might have been barking up the wrong tree for a while.

OK Guys-I appreciate this. I will if not to tired in in my older years after work pull the back cover "carefully" and take a look and post some pictures. I had got the impression that the PO had some knowledge of this so maybe he put in a RPM rod fingers crossed we shall see. I do not want to take a chance on a premature failure for a extinct parts wise engine. Worse case scenario I guess I can source a new Nitro 90 size engine if there are any Manufactures out there still making them? or go back to 26cc gas but I have Nitro in my veins and prefer the sound of a high wound screaming one over gas. No offense to the gas Guys out there.

OK Guys here are the pictures. I cannot tell if it is needle bearing rod. I noticed there was a steel disc to operate as a valve for the Carburetor on the rear cover? I was careful not to knock it out of time and put it exactly back into the same notch with pin off the rod. Not sure if it would make a difference or not but all the same. I looked closely at the rod looks to be steel? do not see a bronzed bushing when I wiggled it slightly off the crankshaft? Is this the rod style that like to fail? Thanks Ken

Rudy Formanek said:

That motor is not a P-90, It is a H-90 (Hydro 90) with a head someone has painted blue. The last model of Picco 90's were called Bluehead 90's and had a factory fuel pump mounted on the side of the crankcase above the carb. Your pictures helped show what model this one really is. The hydro 90's came with a needle bearing rod and instructions to change it out to an RPM rod. People who ran the stock needle bearing rod were treated to a crankshaft pin that looked like a squirrel chewed on it. Later the Picco Hydro90 was shipped with a New RPM rod included in the box. If it was mine I would not run it with out changing the rod.

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Rudy is correct, this is a H-90. I still have both the P-90 and H-90 motors and plan on hanging onto them through this summer or longer to see if I can get one of my Twins running this summer. Sorry I do not have any extra parts, like the RPM rod.

ktucker8 said:

OK Guys here are the pictures. I cannot tell if it is needle bearing rod. I noticed there was a steel disc to operate as a valve for the Carburetor on the rear cover? I was careful not to knock it out of time and put it exactly back into the same notch with pin off the rod. Not sure if it would make a difference or not but all the same. I looked closely at the rod looks to be steel? do not see a bronzed bushing when I wiggled it slightly off the crankshaft? Is this the rod style that like to fail? Thanks Ken

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Ken, This has all stock Picco parts. It has the caged bearing between the crank pin and rod. If you want to take a closer look at the rod roller bearing lightly tap the motor case on a table or wooden board and the roller bearing should slip off onto the table.

CMB & Nova Rossi both make 90 sized engines. Contact Stuart Barr on here for CMB & Ron Shaw also on here for NR.

The rod doesn't fail, it brinnells the crankpin surface and the tiny pieces go through the motor. May not happen with low nitro.

Oh Boy....so what do you Guys think? Would it run ok on 15% nitro or are these bad enough it will come apart without this upgrade? May have to source another engine if so. Any thoughts on another brand 90 sized Nitro? Seems like most of my Hobbies thinking I got a good deal turns into more money to be thrown into it but hey its a Hobby what can I expect? LOL! Thanks Ken

Use fuel with 20 oil content and run until it breaks then buy new. Or you could sell it and buy a new CMB or Nova. If 20 or 30% nitro boat fuel is not available from hobby shop you can order it or someone here could tell you how much castor to add.

Brad

moparbarn said:

CMB & Nova Rossi both make 90 sized engines. Contact Stuart Barr on here for CMB & Ron Shaw also on here for NR.

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Thank you for the info. I am thinking of just running it and see how it goes but pick up a new engine to have set aside for back up. Unless this one is worth more being new perhaps selling it and getting something else with the funds may be better. Disappointing since I really thought this would be a mean engine to run. Ken