Re-Build???

[wineguy069]

OK, my boat runs quite well right now (so I shouldn't mess with it). However, YOU have turned me into a speed junky. So, I was wondering what should I set as a budget number for a re-build? Realize I want something reliable since my family like lake recreation. Should I just change the intake and headers or does that also neccesitate going deeper?

[Moneypitt]

More info is needed to give you an opinion. I will say however, that a good running average speed boat, should be left alone and enjoyed. There is an old saying that if you have to ask what it costs, you can't afford it...And it sure applies to boats, I know that all to well. Seriously, consider leaving your existing engine alone, and buying additional parts and pieces to build a complete hot rod motor. That way you can still enjoy your boat while slowly assembling the hot piece. Then if anything happens to the hot rod, and as you read here, something always happens, you can still re install the original motor and have fun with the family... Just my .02...Moneypitt

[AZKC]

At least intake, carb and camshaft. Maybe some ignition upgrades. Then do some pump work. Headers I keep going back and forth between the benefits and the draw backs :confused:
Sometimes turnkey complete motors are the way to go, if you build them like me :D
KC

[BiggusJimbus]

How much of the work are you willing or able to do yourself?
What are your speed goals?
What kind of shape is the bottom of your hull and your pump?
If you can do your own assembly, you should be able to build lots of reliable power for about 3K in parts and machining. If you need up upgrade your exhaust (And you probably will to take advantage of the other work), figure 750 to 2500 depending on what kind of exhaust you want.
Let's see a pic. of this boat. That'll help with the suggestions.

[Cas]

wineguy,
With your big heavy boat, you will need to build quite a bit of power to get it moving and to keep it there. Along with all the engine mods, you may need to do some hull and pump work.
You will definitely notice a difference with a new intake, carb and cam. As far as headers go, I believe you have a covered engine , so the headers you need are water jacketed. You're looking at around $1500.00 just for the headers.
All in all, my guess is you'd be into the $5K range pretty quickly......probably more

[wineguy069]

Ok, here are some photo's. The jet was rebuilt last summer but the seal has leaked ever since (GT boat has re-done it 4x so far). Took the boat out this weekend and although it pulled everyone around ok, it ran rough. Started the weekend adjusting the timing to get rid of some misses at WOT---seemed to work.
1/2 way through Saturday, amp meter went to 0 but boat kept running... Sparadically moved to a normal setting then back to zero... Anyway Alternator is less than a year and the boat went all weekend without draining the battery.
Put 40wt oil in before the weekend and watched the presssure guage closely. Was all over the place, from next to nothing to what would appear normal maybe 60-70.
Idle was good and WOT seemed fairly smooth but in between was rough like pulling a tuber out of a turn and going up to around 3500rpm..
Early morning starting the idle was rough for a short while and smoothed out with a few revs...Also some white smoke out of the exhaust (I guess I am bleeding oil :( )
Also paid attention to WOT rpm - just over 4,000.
I can really hear the valves clicking away, I am new to boating and having an engine that close to me while running at higher rpm's is this normal or is there possibly more wrong inside?
There are also some picks of my hull. It feels pretty solid in the water perhaps these dings are only cosmetic..
Enough for now....
Grady
http://home.pacbell.net/gsibert/boat/boatjet.jpg http://home.pacbell.net/gsibert/boat/boatprofile.jpg http://home.pacbell.net/gsibert/boat/engine.jpg http://home.pacbell.net/gsibert/boat/hull.jpg http://home.pacbell.net/gsibert/boat/hull2.jpg http://home.pacbell.net/gsibert/boat/jethull.jpg

[TIMINATOR]

A typical 50-60-mph jetboat takes about 20 Horsepower per MILE-AN-HOUR GAIN,Just thought you should know that.It may change your idea of what to do.Cam,intake,and carb, mebbie 60 hp or 3 mph, and for only $450 in parts + don't forget to add the labor! Talk to a GOOD ENGINE BUILDER BEFORE spending any money.Talk to the fast guys at your lake and see who built their stuff. The more people you ask, the better off you will be. Also notice that the lake contains MANY: liars, B.S.Artists and general incompetents.Make sure your B.S. Detector is active, or bring someone with you that speaks motor,and has been around the block a time or two. TIMMINATOR

[BiggusJimbus]

Sounds like you have a bad ground and probably a bad cam.
From the looks of things, you are due for some serious work. Decide how much you like the boat and set your budget accordingly.
You might find that for what you have budgeted plus what you could get for your boat, you could go out and find a real nice properly built setup that somebody has decided to move. Just got to be careful that you aren't buying somebody elses problem.
Sure is quicker getting back on the water that way too.
Good Luck. Don't jump to any conclusions.

[Jungle Boy]

I'm with Timinator on this. Do what you can on your own, but if you have to guess on the serious stuff, farm it out to someone that knows "BOAT MOTORS". Sure you can go out and spend a bunch of cash on parts and bolt them on, but the only thing you'll get out of that is more practice in removing your engine and putting it back. MOST off the shelve parts need some machine work to get the most out of them. Some backyard machanics would like you to believe that you can grind your crank and do a valve job with a axe. Do it right once and you'll be happy for a long time. It looks like you could do a lot of cleaning and detailing while the engine is being done. Put your boat on a diet and you'll see performance gains too. Jetboats are very weight sensitive.

[wineguy069]

From my opening post, remove the "runs quite well" and replace with "runs" :) .

[Jet City]

Buying a hotter boat is always an option, and if you have plans of going very fast, I'd recommend it. But you can add reasonable amount of power to your existing mill if it is still somewhat tight (good compression and oil pres.). I have an 18' 460/Panther boat, its engine looked much like yours when I got it, crusty, original and needing some help, it ran 4400 rpm at 49 mph. I ported the heads, new valve seals, Comp 268H cam kit, Weiand Stealth manifold, 800 Holley DP, recurved Prestolite distributer with Pertronix module and MSD coil & wires, this (with tuning) now goes 55 mph @4900 rpm's and is far more rev happy. The next stage will be ported small chamber heads (raise the compression from 8:1 to 9.5 ish) Comp 280H cam kit and headers which should get me into the 60's, I know, big deal, but for me its still fun and I've done this on a very small budget, most parts were bought used and all were installed by myself without disabling the boat during the summer.

[wineguy069]

Here is an update. After some more reading on in the forum, I decide that perhaps the new plugs I put in last week were gapped to wide. Managed to find one of the old ones and it was .035 vs the .045 I used. So I began re-gapping. Anyway I had also replace the plug wires and cylinder #2's wire was really torn up and I just marked it up to age. However the new wire is in the same shape now... Closer inspection reveals my header gaskets shot. The good news, all the plugs look nearly identical so at least there is consistancy, and they match "The Best" on this NGK link NGK Plug Charts (http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html)
Also, I found out the compression had been checked withing the last year and was in good shape (trying to find actual #'s)
http://home.pacbell.net/gsibert/boat/header.jpg http://home.pacbell.net/gsibert/boat/plug.jpg http://home.pacbell.net/gsibert/boat/plugwire.jpg

[Moneypitt]

You've got an HEI ignition, and the .045 is correct for the spark plugs. The coil in the cap system should put out about 45K. plenty of spark for a .045 gap and the plug life will improve. As an example, a standard (coil less) Mag type ignition is 24K, and the plugs are gapped at .018....Moneypitt

[wineguy069]

Thanks Money,
OK, is this to Ghetto? In the above header pic I showed where the header is cracked (actually both headers are cracked in the same spot). I was thinking of replacing the gasket and using some of that exhaust repair goop to fix the cracks. Any thoughts? Trying to avoid $1500 worth of new stuff.

[Moneypitt]

Find someone that can heliarc the crack, and watch for a set of used exhaust at a good price. There are deals out there, you just have to find them.......

[sidewound]

Doesn't look like a header to me. Kinda loggish lookin. Can be welded but i bet if they are cracked there the flanges are probably crap too. I got a used set of hardins for 150. 80 to have the flanges machined and presto!
http://www.***boat.com/image_center/data/500/114moto_001-med.jpg
I had my stock berks welded and they lasted an hour before they busted in the same spots. If ya get em welded make sure it's not some GOMER that's gonna spool gun'em and grind off his shitty lookin bead. That was 65 clams WASTED!!!!!
Peace Man :cool:
CESAR

[Cas]

wineguy,
I found these on ebay, thaght you might be interested.
Nicson Exhaust Logs (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=31285&item=2424858784)

[Cas]

I just found out a friend of mine has a brand new set of Edelbrock exhaust logs that he wants to sell. He made some grumblings about $150.00 plus shipping.

[BiggusJimbus]

Hey Cas,
Maybe I missed it, but I have never heard of any marine exhaust products by Edelbrock.
Are you sure about this?
Jimbus.

[BrendellaJet]

Edelbrock used to make them, not anymore, unless they just started again(doubt it)They are probably not new, but could still be useable.