Alumacraft MV1448 Seadoo IB jet, Still jetting

Fish On Fabrications
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Mine's a 720 so...

For the tin work, fold up a bunch of old towels, about 4" of them and use them as a base to tune the metal into. Wear some gloves, keep hitting the middle of the towel pile while turning and twistingt the metal to form it how you want.

Jamie
 
I gave it a shot tonight in some pretty good chop. Not good. heavy cavitation. Almost seems worse than before. :cry: I will try it again when it is calmer and see what happens. If it is still bad I guess the cutting wheel will come out.
I have thought about dropping the pump 1.5" lower than the bottom of the boat but I am not sure if it would help.....
Time to go drown by sorrows in a Busch Light and a plate of crappies.
 

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Well, I can see why it wouldn't work now that it's on the boat and painted, knock that big arsed hump down some more and try it again. On the boat it's way too aggressive. See how abrupt the bottom curve is at the back and how steep the back wall is? Not good, water is going to curl and aerate there. Look at a table spoon how the bottom deflects and pulls water under the kitchen faucet with a steady stream coming out (non aerated).

I'd consider knocking everything below the middle strake down and trying again.


I uncovered mine yesterday and started cleaning it out for the season.
Jamie
 
Figured I'd throw up a quick update, cleaned out the hull last night, Zep industrial stregnth cleaner works great to loosen oily grime and slime. Brother donated a bunch of aluminum road signs to make hatches out of so I'm going to try and kick this into high gear and get the decking finished.

I also have two weeks layed off at the end of April so I'll get some stuff done.

Jamie
 
The bat boat... =D>

That's pretty good, especially since we fly down river late at night. Heck, our normal summer bass fishing trip ends around 10pm so other than flying Helgramites, the bats are the next biggest challange to running the river.

No real update to the boat, the grease and slime is all gone, but it stormed so now it has tree buds and other crap in it again...
Jamie
 
man this boat is too awesome. your craftmanship is great. wish I had a 1/3 of your skill. do you have any updates and new pic of it? I now you hear it alot but I would love to see a video of it. I really want to see the holeshot. thanks for taken the time to post it and sharing it with us and given me ideas that with my skills I can only dream about.
 
Midnight, thanks for the compliments. I've been slow getting back to the boat. We did manage to take it out last Wednesday with mixed results. First trip of the year and I found out that both pop off diaphrams in the carbs had burst so it wasn't fueling correctly and some was leaking into the bilge. We were running 40mph at 5k and ran it for about thirty minutes up and down the river trying to use up last years fuel and get the cobwebs out. I put a new pump on and I can't wait to crank this thing up to 6500rpm. I also made an engine cover last week at work out of a traffic sign. No pics yet but it turned out pretty good.

It was nice to hit the water again.

I have about five big project bidding for my time right now and the boat is one of them.

Jamie
 
I would like to see how the engine cover turned out.
I cut my spoon off. I decided (per your advice)to angle cut the center rib down in the back (sloping towards pump) and welded it up. I am through messing with it for this year. Time to fish !! Next year I may try the spoon again out of UHMW, I will see how it performs this way.

SDOG
 
Quick update, burnt up the engine in the fiberglass boat today, raw water thermostat didn't open and it truely is bad when you get the burnt oil smell and the paint is bubbling... Pisser is I cleaned it all up before taking it out to get some on the water pics before I sell it. At least it's only a 2.3l Ford so it should be a painless swap...

After that fiasco took the little one out this evening. The back cylinder was missing and it wasn't running very well. Did an on the water plug check and the front one was dark and the back one was wet. Tapped the gap closed pretty tight and hoped for the best. With the new pump on the boat will do 52.8mph on the flat and has more of a growl vs. the old screaming exhaust tone. I have the big purple expansion pipe setup on and it was only taching 6300rpm so maybe I'll put the grey one back on to see if I can get it to rev a bit higher and maybe see 54 mph. The '95 Seadoo Xp ran 58mph so anything over 50 is pretty darned good. I'm happy. There's no rooster tail now, just a skim of white water the with of the bottom of the hull and very little wake. I did run down a 16-18' Grizzly with a 90-65 jet and went by them pretty quick when I ducked behind an island.

Jamie
 
Awesome!

I am going to have a few more questions for you once I finally save up enough to start mine with the 650 Rotax.
 
Today's great accomplishment was getting the dug house for over the engine built.


But first, last week I finally got tired of waiting forever for the boat to drain so I drilled a second drain, 1" this time to fit a standard plug. It worked great so I redrilled the original 3/8" NPT port to take another plug.

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The doghouse, not saying I vandelized a street sign or anything (it was out of service). The vent came from an old computer tower and fit pretty well.

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Only real screwup was I misread the tape measure for the top dimension. Maybe I'll do something to make the mistake look like it was done on purpose. I may add a piece of round to the rear edge to keep the stubbed toes at bay.
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I also finally ordered the piano hinge for the all the covers. Only real expense after this is the carpet for the decking and the epoxy for the hull.

Jamie
 
Fun trip tonight. Hit the water around 7:30 since it was too hot to fish ealier. I spent Tuesday evening taking the carbs apart and cleaning them really good and setting everything up to Seadoo specs and now it's running up to speed but just because, the linkage between the two carbs fell off, several times... Finally fiddled up a big hook to hold the darned thing together. Oh yeah, the expansion pipe is coming loose again. I was going to swap it but lost the silver one I had so this one is spiting me.

Still good evening on the water, hit a 13.5 and a bunch of little stuff. Just got home too.

Went out Monday and the boat ran like crap but we did see the Black Bear runnning around Williamsport on the way home. Looked like a bag of trash running across the lawn of the church :)

Still waiting on the hinge to get some decking done...
Jamie
 
I see that you are having vibration loosen everything up on a regular basis. If I remember correctly, when you were building it, I remember seeing that you made your own engine mount plate, that was flat to fit the boat, as opposed to the angled one that fits the Seadoo. I'm wondering if your vibration problems are due to all 4 engine mounts being on the same plane, as opposed to the installation in the Seadoo, where they were a number of degrees apart.
 
Possibly. The engine hasn't been fueling right and had been shaking pretty hard the last couple trips while I worked the bugs out. The last time I put the expansion pipe on I didn't silicone it very well. Otherwise it hade been holding up pretty well.

Jamie
 
Holy crap!! =D>

I just read through this thread for the very first time. Amazing. My jaw is on the floor.

To think, I was so proud of myself for installing a deck hatch in my boat. I feel shame. :oops:
 
Yeah, this is fun because it's not a production boat. We outran a tracker inboard jet last night too, I think it was one of the newer 185 jets. We haven't ran any white water yet, I'm scared, and I want to work all the bugs out of the motor before hitting the scary stuff. The lower basin is filling with grass so we are running up to the ridges and rock breaks. It actually lower now than when the grass blooms on top of the water and the flow backs up.

Kind of fun running Frankenstein.

Jamie
 
Brief update, took the boat out last night, with a carb linkage that stayed on both carbs and an expansion pipe that didn't fall off. Ran the boat up river through lots of traffic, 40+mph at 5500rpm, 50.9 at 6700. The motor isn't too happy down below 3000rpm, I still don't have the carbs dialed in and it acts flooded when I start it, need to reset the pop off pressure on the needle and seat of both carbs. Wind was terrible, white caps on the water but it only cavitated when I went through another boat big wake so the spoon is definately working.

Coming back down we went through two flocks of geese in the channel. Usually they take off and pace us but these had young ones with them. Chopped the throttle and the bow wave surge pushed all of them out of the way except one old biddy that turned and postured right before going under the bow. She didn't see too much the worse for wear in spite of losing here dignity when she came up behind the boat.

We were hot dogging it dodging weed clumps logs and beavers. The boat will do the jet boat slide below 30mph and really skews out around 20 but I swear the inboard gunnel is under water at the back corner. had a lot of fun and made it home before dark for once since the fishing wasn't so great with all the wind. That and the boy lost his favorite lure, came untied and then a nice bass hit it as we trolled in to get it... He was pissed. :shock:

Jamie
 
BaitCaster said:
Holy crap!! =D>

I just read through this thread for the very first time. Amazing. My jaw is on the floor.

To think, I was so proud of myself for installing a deck hatch in my boat. I feel shame. :oops:
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Ditto
 

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