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Thread: loss of power

  1. #1
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    Default loss of power

    Hopfully some one can help, new to boating. I have an 18' almar lite with a volvo penta 145a 4 cylinder, and a hamilton 770 single stage jet. Took the boat out yesterday and it did not have enough power to get up on step and by the end of the ride had almost no power with engine at 3500 rpm's. Checked the jet unit for any clog of debrie and none, could this be a torque converter problem? Any help appricated!

  2. #2

    Default May help...

    Hello penta, im not familiar with your set up but have an idea or two that may help. Is 3500rpm's on your motor a usual high rpm or mid? If this is a higher rpm for your setup and your are just not getting the push you normally would get. I would take a look at the sleeve around the impeller and see if it needs replacement or check your impeller for deffects. Take a gap tool to check spacing. Hope this helps, im not familiar with inboard set-up but with outboard jet thats were i'd go after the checks you have already done.

  3. #3
    Member chriso's Avatar
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    Quote Originally Posted by penta View Post
    Hopfully some one can help, new to boating. I have an 18' almar lite with a volvo penta 145a 4 cylinder, and a hamilton 770 single stage jet. Took the boat out yesterday and it did not have enough power to get up on step and by the end of the ride had almost no power with engine at 3500 rpm's. Checked the jet unit for any clog of debrie and none, could this be a torque converter problem? Any help appricated!
    Check again... there is often stuff inside and even in front of the impellor that will foul your flow. When was the last time you had the impellor rebuilt? I assume it ran fine last fall?

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    Member broncoformudv's Avatar
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    Quote Originally Posted by penta View Post
    could this be a torque converter problem? Any help appricated!

    Jet boats do not have torque convertors they are directly connected to the shaft the impeller is on. Did you just buy this boat or have you owned it for some time? How was your performance when you first started out the other day? It does sound like your jet is plugged up. Did you hit any gravel bars or sand bars while running it prior to losing performance?

  5. #5

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    That motor is famous for going through valves and the carbs are somewhat difficult to get adjusted together. Make sure both carbs are opening/closing at the same time and adjust as needed and then give it another try.

    Ours lost power due to a burnt valve and showed no signs of going before it couldn`t get on-step anymore.

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    You know something.. I might think I'm the new owner of this boat.. The motor runs fine and revs up nice and sound nice and smooth. The impeller from the rear looks good.. A couple rocks in the grate, but cleaned them out. I backed in in the chena the other day and seemed to thrust well for me..

    I couldn't get it up on any speed the motor would rev just fine.. Any help.. It's an 84 Almar lite with aq145 volvo penta 140 hp with the Hamilton 770 drive..


    Any real help please?

    Hopefully I wasn't swindled here..

    BTW this was a trade-in at Salcha marine and I was assured that it was in working order... Totally ruined the fishing trip this weekend.

  7. #7

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    Do you mean to say that the engine will rev. as you think it should but there is not enough thrust to plane the boat ?

    If that is the case the impeller needs to shimmed or replaced ( and liner) nad the outlet and intake inspected for restrictions.

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    Member SusitnaAk's Avatar
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    I would take it back to that marine, tell them to fix It !! also i think you should be able to get 4000-4200 rpm,s out of that motor,If than not and option. take the jet apart check the stator, this are very simple jets to work on.http://www.riverjetmagazine.com/fuse...orum/index.cfm Dig around in here good form also
    Last edited by SusitnaAk; 08-25-2009 at 07:46. Reason: more

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    After talking with some folks, it sounds like the impeller is worn out. I'll have to take it down and look at it.

    The motor has tons of power and rpms. I don;t think it's lack of power on the motor.

  10. #10
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    Turns out the Impeller was really in insanely bad shape. Two of the vanes were bent up. and the leading edges were looking like hockey sticks with the amount of wear. Turns out there was .074 gap between the impeller and the wear ring. Couple dings in the stator too. I had a guy clean up the stator and rebuild the impeller.

    Much better now, went up and down the Chena tonight moose hunting and it did fine. Topped out at 4000 rpm now.

    Thanks for the info and help guys!

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