SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: steves86ta on June 03, 2013, 12:01:33 PM
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Hi Guys,
I got the new engine in the boat last weekend and headed out to Perris yesterday to get her broken in and see how she runs. I was very happy with my results, however I now believe the stock Qjet is too small, or just not ideal.
Here are the specs of the engine;
Vortec 350 (stock bore)
Custom cam (224/224, .503" at 1.5 on a 110* LSA installed at 108)
Stock vortec heads for now plan on replacing with Edelbrock E-Tec's
About 9.5:1 compression
As far as performance goes, the boat runs great. It pulled the 19 pitch prop I already have o 5100 easily and 56.9 mph via GPS. (I could have pulled more RPM if I trimmed out more, but I did not want to run the stock drive that high) I plan to "prop" it down to where WOT is about 4600.
With that being said, the engine really was a dog out of the hole especially trying to Ski. I changed to my 17 pitch prop to try to pull some skiers and it just has a very hard time when going from idle to WOT. Seriously bogged down and had a hard time building RPM from idle. My thinking is that it is either Carb related or Timing related. I have the initial timing set at 10* and it just seems like a huge bog.
So my question is that I want to get rid of the Qjet and switch over to a "traditional carb" I just can’t decide between a double pumper or a vacuum secondary. If this was a car I would go with a vacuum secondary but I do not know if a boat will run a vacuum secondary carb efficiently when you are at RPM all the time. I know most everyone recommends a double pumper when pushing a Jet, but I have an outdrive so would a double pumper still be the recommendation? Also what size I’m thinking no bigger than a 750.
Sorry for the long post, but thank you for any insight you can provide :-)
Steve
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ok this is just an opinion so take it for what its worth. just have your Qjet rebuilt, i personally dont like them but when they work they do well. second dont use a vacuum operated secondaries carb on a boat. good luck.
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Yeah i have thrown that idea around, and frankly i have another Qjet sitting here that is a fresh rebuild. I will need to modify the linkage to make it work. I may try this one out and see what happens
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that maybe your best bet!
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Quadrajets are good carbs with them big ol secondary's ,
Sent from Wendy on my iPhone using SoCalJetBoats mobile app
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Steve, do you wanna try the edelbrock for sh!ts and giggles?
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Steve, do you wanna try the edelbrock for sh!ts and giggles?
Thanks for the coffee Shawn, but I found a 750 double pumper on Craigslist tgat I picked up and went through. Got it on this weekend and it sounds way way better than the q jet did. Just need to get out there and try it out.
Thanks for the offer though.
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Nice! I'm pretty happy with mine, just trying to work out the bugs. Bugs are just a lack of experience on my part!