Jetstar boats

[alanr]

Hi, I have just rejoined this new site and as one of a small team at Bluebird Marine I built the Jetstar 390, 400, 520 and 525 boats. If anyone needs any help or info about these boats I would be delighted to assist. Alanr.

[BN]

Hi Alan, thank you for highlighting the 'cut off' problem and welcome back. BN

[enginuitytriumph]

[alanr]

Hi Mark. I assume you have the 3 litre V6 engine coupled to the 05 jet. This should give a top speed of 45 mph @ 5000 rpm with 29/37 gears fitted or 4800 rpm with
28/38 gears fitted. The standard nylon impellor is perfectly adequate for power up to 150 bhp so forget the s/s one. Check the impellor housing for wear because if there is a gap between the impellor blades (new) then static thrust is reduced making it harder for the boat to get on the plane. However 32 mph is very low even with a worn impellor and/or housing and I wonder if water has got under the floor sections and is adding a lot of weight to the hull. Try drilling a small hole through the side of the floor to see if any water comes out.
Check the reverse bucket is fully raised when going forward to get full thrust from the jet. Do you have the rack and pinion steering or is it the early cable and pulley system? Ensure the rudders turn easily by removing the tail housing assy and move the rudders by hand. It is possible corrosion has caused the delrin sleeves to tighten on the rudder shafts. The steering was never particularly light on the 05 but it should not be giving you problems.
Do you have any pics you can show me of the boat, engine and 05 jet?
I should be able to give a year of manufacture.
Hope this helps.

[enginuitytriumph]

Hi Alan,  thank you very much for the reply, its nice to have a real expert on board rather that a  'I'll have a go!' Yes its the Ford V6 with the 05 Castoldi. No idea of the gearing, I've not had that apart .... yet.     I intend to make the heads unleaded & a little porting for torque & Kent cams said they can make me a 'torque only cam. I don't think I have water in the hold, but I will check & the reverse bucket doesn't lift completely, so I'll adjust that!      Is there a max gap between the impellor & housing ( my yamaha jet boat there was a max clearance setting ).    I will try & do the pictures over the weekend, here are a couple of snaps for now!.  I was told all the boats were named & I couldn't find one ( sniff ) or any hull numbers, is there a place to find those?
I haven't even dared to take off the rear casing to check anything, so I'll be brave & take a peek to check the rudders, it has got the Castoldi rack & pinion steering. If I could get 45mph I think I'll have to buy a round !!   all the best.... Mark

[alanr]

Hi Mark, this boat originally had the standard seating with two front bucket seats, a rear bench seat and a full width engine cover. I think it was a 1975 boat and our directors were approached  to loan a boat for an expedition to the Chagos Archipelagos headed by HRH Prince Charles. They agreed to loan the boat which had to be modified to have 6 seats so you have the only V6 version of 520 like that. The only other time we used that arrangement was with the BMW 6cyl engines.So your boat spent 2 months in the Indian ocean giving fun to the expedition!
When new the impellor almost touches the housing wall. A gap of 2 mm will decrease the speed a little but not much. However the bigger the gap the lower the thrust before cavitation begins, which extends the time taken to get on the plane. What RPM is the engine attaining?
I look forward to seeing more pics.

[enginuitytriumph]

Hi Alan, thats absolutely brilliant, gobsmacked !!  how can I follow that, but I don't suppose you remember the name of it? I will try & pop the rear casing off tomorrow & see whats going on. Unfortunately the rev counter, fuel gauge & speedo where my 'faults to live with' last year! not so this year!! When I took the seat frames out, they were marked P/S & the seat bases & backs were also marked, making my job a lot easier although I didn't keep the original colour scheme. The engine cover was very well made & very heavy, I have hinged it rather than have to lift it off every time. the swim platform took me a weekend to make with some teak I had left over from a garage door I made! here are some more pics before & during the 'quick restoration'. I will take some more detailed ones if time & weather permit as its only in my drive, but under cover! thanks a million... Mark

[enginuitytriumph]

sorry, it wouldn't let me put any more pics on, so re-sized these ones....

[BN]

Hi, it had to have its own section.
Sorry about the pictures, but it is down to bandwidth and I have to limit the size because I keep the forum going on my own and with the greatfully received odd amounts of sponsorship monies.

[alanr]

Interesting to see trim tabs fitted. We never used them although I can see the benefits in getting
a heavy load onto the plane. We never named boats ourselves unless it was a demonstrator
or my own personal boat which had the BBM name and Jetstar logo down each side.
Any boats that had a name were by the owners choice and was sign written accordingly.
Incidentally I think the Chagos expedition was in 1977 and was by our joint forces.
Boats were not numbered but logged by both the engine and jet unit serial numbers.
I am fairly certain your 05 jet will have 27/39 gear ratios. This is usually stamped
on top of the gearbox casing not far from the oil dipstick. The engine should attain 5000 rpm.
I look forward to seeing more pics and to find out what rpm your engine is reaching.
Alanr

[enginuitytriumph]

[enginuitytriumph]

Here's a couple more....

[BN]

At least you can get your bits off  , my Dowty has been a battle all the way 

[alanr]

The pics are fine. I managed to enlarge them and they show the jet unit to be in good condition. The impellor housing has the usual fine grooves in it caused by sand and small stones passing through it but this is normal. A new impellor will help to increase static thrust but there won't be much difference in top speed over the old one as it is not worn out yet. A new impellor will just touch the housing. This is normal. Raising the reverse deflector above the lip of the discharge housing will allow the water to flow cleanly and should increase top speed.
It will be interesting to find out what rpm the engine is achieving.
I have pics of various 520 boats and will post some on here when I can.
Alanr

[enginuitytriumph]

Hi Alan,  I'm going to try & get the old girl on the water for the OSB test day at Chichester Sunday 25th March, need to check everything is OK for then & get the rev counter working !! & I'll see if I can get top speed on the that small lake !! fingers crossed... Mark