checked the speed on the GPS today

[dgie]

I got an eye popping 42 mph max at 4200 rpms max. I understand that I should get about 10 mph faster at least on the stock 455 olds and Jacuzzi 12wj pump. I am not if the pump is cavitating. CP performance told me that if the boat does not feel like a slipping clutch then the wear ring is fine. When were running the motor in the begining we were running it dry with no water in the jet. also not sure about the impeller seems ok but not sure if it could be the culprit. currious if anyone has any input on this. I took pics of the boat today, will try to post them tommorow.

[victorfb]

hummm? seems a bit low on speed at 4200 rpm. and if you ran the boat out of the water, and especially dry pump its a good indication that the pump was hurt. i myself do on very rare occasions start the boat out of the water but i hook up to a hose plus i squirt water in the grate while doing so. and never run it for long preiods of time or high rpm's. i hope you didnt hurt it but you may want to have it checked out.
BTW, 4200 rpm is about right for a stock olds with a good pump.

[dgie]

I think that is a good idea, I found out late about it being bad to run the pump dry. No problem I had it apart once and rebuilt it myself. So I am a veteran at that. Hey just curious when installing the mechanical fuel pump do you install the pump with the inlet and outlet ports where you attach the fuel lines to, up or down. I am wondering if I am installing it upside down.

[victorfb]

ill have to take a look at mine in the morning, but i do remember the fuel pump having a long (maybe 2 inch) tube looking thing going "UP". it is offset from the center and toward the block. but if i remember correctly the fuel line was connected from the bottom side of the pump somewhat.

[dgie]

I had mine mounted with the fuel lines (in and out) on the bottom looking down on it. I hope that it is in upside down because i looked inside the port for the fuel pump like everone sugested and sure enough it is hitting the timing chain. If the pump was installed right then I have a timing chain issue. Let me know what you find out. I noticed you are bailing on the 455 for a 454, that might not be such a bad idea for me too. that leaves me with only one final problem, a jacuzzi pump.

[Taylor LP]

You know I may be wrong here, but I don't think they are talking about the pump itself being upside down. I think they are talking about the pump lever being on the wrong side of the eccentric that drives it.
I could be wrong, I've never had the pump off of my Olds 455 (car).

[wsuwrhr]

I may be comparing apples to oranges here, but I'll give it my best shot.
I have a Dodge 440 in my 19 foot Anthony with a WJ pump. I ran my boat at Needles on GPS and it ran 53. Pretty dissapointing. Motor runs at 5000 RPM's.
I am running a shoe, stock (Berk)Legend "A" impeller, my bowl is modified to accept the Legend Impeller and I welded a ring on the outlet for Berk add ons. I run a Place droop, with a Hyd diverter for a Berk pump. I made my own hardened shaft that I gundrilled to fit the new impeller.
I don't know if that helps, my combination may be way off still, but I just wanted to post to say you are not alone. haha.
Brian http://www.***boat.com/image_center/data/521/63droopad.jpg
[ June 15, 2003, 09:09 AM: Message edited by: wsuwrhr ]

[malcolm]

dgie- what impeller are you running? Most WJs seem to have a B. 4200 rpm translates to around 200hp, a 455 should be more than that. My 403 Olds turned a B up to 4200. It would usually run about 47 mph at that rpm. This year the motor and pump will be new, can't wait to get some numbers.

[Cas]

dg,
I had a similar situation with my basically stock BBC a couple of years ago. I was only getting about 4200 rpms and about 45 mph in a 21' boat with a Panther jet. The following is what I did along with the rpm gain or loss.
dump the dual point distributor for a electronic - + 50 rpms
Switched to a Torker intake from a Performer 2-0 - very little change
swapped out a Holley 780 for a Edelbrock 750 carb - very little change
changed jetting and metering rods in carb - + 50
swapped Edelbrock carb for a Bigs built Holley - + 50 over the Edelbrock.
The engine is now getting 4350 to 4400 rpm's after those changes.
Since I didn't have any idea what cam was in the engine, I decided to pull it and do some freshening up. I put a very mild cam in it (.515 in/.525 ex) and a bit smaller than the one that came out. New lifters, rings and bearings.
After putting it together, it still ran about 4400 rpms, maybe 4450.
The next change was to go with a Edelbrock RPM Air Gap intake and gained 200 rpms.
The engine is now running at about 4650-4700 rpms and hitting 57 mph. I know it's not any kind of a speed demon but it runs real well in the 21' Tahiti.
One area you may want to check closely for is a vacuum leak. Start the engine, let it idle and spray (using a spray bottle) the joint between the intake and the heads, the base of the carb and where the linkages come through the carb. If you hear any change in rpm, more than likely you have a vacuum leak that can cause low rpm's.

[Tahiti Tiger Mark]

My 18' Tahiti Tiger with 455 olds, berk jc pump with A impeller does 61 mph (GPS) at 5200 rpm. At 3500 rpm the mph matches rpm of 35 mph. I am thinking my pump needs a rebuild bad. The guys at CP told me if I rebuild I could get another 5 mph possibly. Is there a way to keep the same mph but lower my rpm? I hate spinning that olds to those rpms, and do not do it often. Try to always stay below 4500.

[BLEWBAYOU1]

tahiti tiger,
I have a JC pump with an A impeller and 460 ford.It turns 4800 rpm w/two peaple ice chest full of beer and two full tanks of gas I GPS at 68.3. with my 18' bubble deck Eliminator.
So I would say you need to have your pump checked out.That's alot of RPM for a "A" impeler.
Brian :cool:
[ June 15, 2003, 10:23 PM: Message edited by: BLEWBAYOU1 ]

[Rexone]

A lot of it depends on the boat too. And weather it has a hook in the bottom. Did this boat run faster at some point or you don't know? Also at 4200 RPM I doubt the pump is worn out or the RPM would likely be higher (and boat would be slow).
Also you need to solve your fuel pressure problem before you start blaming other things. Always fix one thing at a time so you know what's changed what. Just my addl .02 :)
[ June 15, 2003, 01:56 PM: Message edited by: Rexone ]

[dgie]

It seems that I was putting in the mechanical fuel pump backwards. Thanks to a response I got from a member. I put the pump in correctly and it pumps real good pressure. I was half way to the lake when the weather started to piss rain all over me. I will check it tomorrow on the lake if it nicer out. I will see what kind of readings I get and then pull the engine and tear into the pump. I had the engine out of the boat so many times it is nothing to pull it and it worth a check. Believe it or not I used to build jet engines when I was in the Marines and they were easier for me. Probably because I was actually trained and went to school for it. Wish I had one of those turbo shaft motors 1200 shaft horsepower would spin the hell out of that pump. :D

[dgie]

I want to post pictures of my boat on a reply post can anyone instruct truct me how to do this?

[Snorider]

dgie, e-mail them to me (snorider@ptd.net) and ill put em up for you for now.
If you wanna do it yourself, here is how:
Put the pics on a publicly available website (so you can access them by http:\\<something>. Then, when you create your post, click the IMAGE button below (in the instant UBB Code area). That will give you a popup asking for the image address. enter the web address, click OK, and you are set, thats all there is to it.

[txboatnut]

Dgie,
gald to here you followed the advice of the other guys and got a mechanical fuel pump. What type of carb are you running? It could be the secondaries are not opening up. If it is a q-jet what type of choke does it have? If it is not a electric choke that could be a issue for you or it was for me. I had a mechanical choke and the heat riser tube was broke which kept it from getting hot enought to let the secondaries open. Hope that helps.
Paul :cool:

[txboatnut]

Sorry,
just read your other post and found you have a Holley. I do not know anything about them but I would make sure the secondaries are opening up.

[dgie]

yes, I have a Holley 750, it has vacume secondaries and an electric choke. The secondaries are infact opening up I can hear them kick in around 3500 RPMs. I will stick with the mechanical fuel pump as long as it perorms tomorrow. I am going to pick up a spring kit for it locally at a speed shop so I can get the secondaries to kick in quicker.

[dgie]

it seems like a real hassle to set up a public site, then post them that way. How are people adding them directly to their posts like seen above? I tried cut and paste that does not work

[Rexone]

register in the hot boat image center (free) and upload them there. Then just do the image thing in your post.

[dgie]

ok i registered and added 3 pics to it, not sure what to do now

[dgie]

well I am lost in the sauce on this one. They are under "darren" in the image center if anyone wants to view them

[Rexone]

http://www.***boat.com/image_center/data/502/740DSC00084-med.JPG
http://www.***boat.com/image_center/data/500/740DSC00085-med.JPG
http://www.***boat.com/image_center/data/500/740DSC00086-med.JPG
There ya go :)
All you do is go to the image center and right click on your "large" image, not the thumbnail, click on properties, highlight and paste the image code to your clipboard. Then go to the post your creating and hit the image button and paste the code into the little pop up window. Make sure you delete the second http/: if there's 2. Sounds confusing but easy once you do it. :)
[ June 15, 2003, 11:02 PM: Message edited by: Rexone ]

[dgie]

cool, thanks Mike

[Frosty_pop]

dgie:
that leaves me with only one final problem, a jacuzzi pump. Nothing wrong with Jacuzzi pumps!!! I would junk the 455. To much weigh and not enough power. Makes a good anchor though. I trashed my 455 a couple of years back and never regretted it.
[ June 16, 2003, 11:20 PM: Message edited by: Frosty_pop ]

[dgie]

good i have a question for you Frosty I do want to junk it but i am having trouble desciding between a 454 and a 350. Some people say that you need a lot of torque in a jet boat and only a big block can provide that.Then others say that river boats etc do just fine on a small block. I am confussed on this issue?????????

[dgie]

Wish I lived back in San Diego again, more to do there then here. Texas is Borrrring. Plus I miss Robertos mexican food, good stuff.

[victorfb]

im thinking about the swap myself. but it will have to be a winter project. i wanna have fun with the 455 still. besides, i still like the idea of having the original engine.
as for the decision between the 454 and 350... i would definatly go with the 454. i have riden in an 18' jet with a 350 and it was ok, but if givin the choice, id have to go with the big block. only decision would be the 454 or 502. hahaha.

[mud duck]

Actually, an Olds 455 is light for a big block. Comparable to a 350 in weight. :D

[Frosty_pop]

Ok heres the scoop..... or atleast my story. I bought the boat with a stock 455, was told it only had 30 hrs on since rebuild. Well it lasted a whole 3 or 4 trips to the river before it went BOOM!! Not knowing much about Jet Boats I opted for a small block to replace it. Lots of time and money went into the swap. Looking back I wish I had gone big block for the tork (sp) But I didn't so I have made the best of it and am now running a 383 chevy on a WJ pump "c" impellor, loader grate and diverter. I can pull a skier no prob. It's not the fastest hole shot in the world, but I can get it up to 67.2 mph on gps at 5000 rpm. It's just a lake/river boat and that's almost fast enough (want to hit 70) for me. Sorry for the long post.....

[dgie]

It could be worse, you could have done something stupid like me and replaced it with the same type of anchor. I was seriosly contemplating the swap before buying the new 455, however everyone I talked to said the cheepest thing would be to stick the same motor in it seeing how I already have the tin to put on it. Oh well I guess its live and learn.

[dgie]

I wish I could go 67 mph. I am getting trashed by boats with trolling motors. :mad:

[Bahner18]

After resding your post I have 2 big questions?????????????What size is your boat and what size is the impeller. Something just dont seam right! If your pump were cavitating that bad you would see way more rpm and out of the hole it would slip like crazy. I have allways seen stock olds engines run great to 5K spinning a a/b cut impeller. You may have way to big of an Impeller cut or to much loader. I have been playing with impeller cuts and loaders for a year now and once you get it right you know it.
Good Luck

[Frosty_pop]

If the WJ he is running in stock it most likely has a Jacuzzi "B" in it. That is roughly the same size as a berk "A". The stock grate doesn't help either.

[dgie]

I called North American Marine Jet (Jacuzzi) and they said seeing how I am only getting 4200 rpms more then likely I need to get the impeller cut down to an "A" which will boost my rpms and hopefully boost my mph. I need to get this stuff ironed out the last time I was out on the lake some guy in a bass boat pulled up to me just as I was fixing to pull the boat from the water and wanted to race. He was running a 150 Yamaha outboard. Had to turn him down, have no idea what those thing run???