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  1. #1
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    New cobra owner, need advice on pad to prop

    Good morning all. Just bought my first cobra, a 99 with a 225 jhonson. Has a jackplate but I know the engine is set to high. Was gana start at 3.5-3.75 and run it see how it feels as the prop is blowing out currently, it's the 18-19 foot model, what do yall have pad prop set at?
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    #2
    There is an 180D,190D, and a 201D, the latter usually comes with a 200-225hp. It looks like 200 on your cowling judging by the pic? Anyways, what prop are you running?
    '99 Cobra 201D
    Merc 250 Pro Xs 4 stroke

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    #3
    Cowling says 200. Engine is a 225. The previous owner put the 200 cowl on to not get in trouble. Prop says 14 1/2 x 24

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    #4
    So prop to pad was basically level, I dropped the ja k plate as low as it could go ansdI'll need to drop the engine to the top bolts cause I'm barely sitting at 3 inches right now

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    #5
    I am running a '03 Merc 225 EFI second hole, on a Slidemaster 10" JP set at 2 7/8" swinging a 26" Tempest Plus worked by Croxton on a '02 201DC.
    If you are at 3" P2P with JP all the way down, you need to move your motor down at very least 1 hole, and maybe 2. If you could post some pictures of the JP mounting set up currently, it would help.

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    #6
    Well I was a Dunce and adjusted wrong way, I know I know amateur hour. Readjusted and I'm sitting at 3.5 and I have another 2-2.5 of adjustment, I'll run it and see how she does, no reason a 180d with a 225 can go faster than 60 and actually raise the bow lol. I realized it when I went to take pictures haha adjusted up not down

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    #7
    Quote Originally Posted by 99Cobra225 View Post
    Well I was a Dunce and adjusted wrong way, I know I know amateur hour. Readjusted and I'm sitting at 3.5 and I have another 2-2.5 of adjustment, I'll run it and see how she does, no reason a 180d with a 225 can go faster than 60 and actually raise the bow lol. I realized it when I went to take pictures haha adjusted up not down
    I think that you should be going a lot faster than 60mph with 18' 180D running a 225 Johnson, which I think it is carbureted.

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    #8
    Quote Originally Posted by digthemup View Post
    I think that you should be going a lot faster than 60mph with 18' 180D running a 225 Johnson, which I think it is carbureted.
    With motor at 3 1/2 she performed great today. Got 72mph out of her but it got extremely sketchy once it hit it. And rpms were still down a few hundred. Hole shot performance is sub par. I think I'd rather sacrifice some top end and focus on better hole shot and stability running 65 ish which I think is reasonable. If I'm running a 14 1/2x24 now what would yall recommend for a prop? Thinking of going to a 4 blade but still Wana be able to raise rpms 2-300 at wot. Thinking stepping down to either a 14x24 or 13.5x24, or other end do 14.5x22

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    #9
    Cobras are known for coming out of the hole, maybe you need to get your prop reworked. I thought maybe my motor was getting a little "tired", I sent my prop off and was amazed at the difference in performance. Having the right height, a good prop, the right combination of ventilation holes, (all open, two open one closed, all half open, etc.) makes a huge difference. But with a 225 on a 188/190, that thing should jump out of the hole. Read back through previous set up posts, but the oeverwhleming majority of Cobra owners agreed that a four blade prop works better on these hulls as they tend to run flatter than other makes. A four blade will give you stern lift and that is what these boats need. Have fun and keep us posted!

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    #10
    I guess I'm co fused on what my rpms should be at running wot on main lake trimed out. I got my tach working I believe it's accurate. I'll have to do some research and find out. I'm also having a lean problem I found out today so gotta address the leak somewhere

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    #11
    99cobra,

    Before you go ahead and start buying props and so on, you need to get some base line number and measurements that you can obtain the best info possible.

    Please post this current numbers:
    What is P2P?= At what motor hole?=

    What is the JP you are running? =

    What is your RPM at WOT?=

    What is your top speed?=

    Are you blowing out or cavitating at holeshot?=

    When was your motor last tuned?=

    When was you prop last B&B?=

    The above information is going to save you money in whatever direction you decide to go, and has your speed increases, you are going to feel that 'sketchy' feeling, since the less hull pad in water to balance your boat, so do not over trim your motor, which will aggravate to problem of chine walk.

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    #12
    P2p is currently at 3 1/4, had at 3 1/2 and had great lift but was still low on rpms, was pushing maybe 4800, my twch is a Lil off I'm waiting for a new tach to come in, it has a 99 jhonson 225, 6 inch jackplate. I'm rebuilding carbs and doing timing set this week on it. Prop is rough I'm buying a new raker and I'll send this one out to get worked

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    #13
    OK, 3.5" P2P is a good starting point to get your baseline numbers, which 4800rpm at WOT is kinda low even for a bad prop. If you are getting a new Raker HO, make sure to get your venting plugs worked out prior to getting it worked on, and I would recommend Mark Croxton for that at later date for B&B.
    I would do a proper compression and leakdown check after your get your carbs worked and dialed in. You said that you are running a 6" JP, but you did not say what hole is the motor mounted to it.
    I would suggest second hole for the mounting hole to the JP, and keep us posted once you get your new tach and prop, plus your carbs dialed in.

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    #14
    Compression is sitting from 115-120 on all 6. I haven't ran a leak down I'll have to take the boat to work for that one. And yeah I can't say without a doubt what rpm is turning since u know the tach is screwy. After my last trip out I tapped it while It was running in a test tank and the needle jumped to 3k so who knows, motor is on 2nd hole mounted to jp, once the new tach comes in and other prop is on I'll get a better idea where I sit

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    #15
    Quote Originally Posted by 99Cobra225 View Post
    Compression is sitting from 115-120 on all 6. I haven't ran a leak down I'll have to take the boat to work for that one. And yeah I can't say without a doubt what rpm is turning since u know the tach is screwy. After my last trip out I tapped it while It was running in a test tank and the needle jumped to 3k so who knows, motor is on 2nd hole mounted to jp, once the new tach comes in and other prop is on I'll get a better idea where I sit
    If the prop has vent holes, I would start with all solid, and see how she come up on plane. If too slow on plane, you will need to introduce exhaust into the prop stream, but that is for another day.
    Let me know what you are getting after you get all your ducks in a row. Talk soon.

    My best to you,

    Frank

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    #16
    Quote Originally Posted by digthemup View Post
    If the prop has vent holes, I would start with all solid, and see how she come up on plane. If too slow on plane, you will need to introduce exhaust into the prop stream, but that is for another day.
    Let me know what you are getting after you get all your ducks in a row. Talk soon.

    My best to you,

    Frank
    Turns out my whole issue is engine related, timing was all wonky, took it to a guy and basically only useful info I got was compression is good. Which I redid the test at himr and dry all cylinders are 112-117. But electrically nothing is "testing" out properly I mean 100-200 ohms out of spec or stuff is open where it shouldn't be. So time for a mini overhaul and I'm just gana replace all electronics that have 1 bad reading

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    #17
    Quote Originally Posted by 99Cobra225 View Post
    Turns out my whole issue is engine related, timing was all wonky, took it to a guy and basically only useful info I got was compression is good. Which I redid the test at himr and dry all cylinders are 112-117. But electrically nothing is "testing" out properly I mean 100-200 ohms out of spec or stuff is open where it shouldn't be. So time for a mini overhaul and I'm just gana replace all electronics that have 1 bad reading
    I can sympathize on your electrical issues, since I know they can be a nightmare to figure out. I am going through electrical issues with my JD 4400 for 3 months, and i am no closer in figuring it out.
    Send me a PM when you get your electrical solved and we will go from there.
    BTW, there is a procedure in doing compression testing, and may i suggest doing a leak down test if you have the gages to do it.