RANGER JACK PLATE QUESTION & PLUGS

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moehuntin

Cadet
Joined
Mar 11, 2006
Messages
9
I just bought a 1986 18 ft 371V 150 G T it has a 14 1/2 24 pitch Raker stainless prop with jack plate. it has very slow take off and the bow doesnt raise much at all when on pad. max rpm,s is 4700 at 55 mph (maxed out) I think the motor is to high cause i compared it to a boat just like it and it is 2 inches higher than his. how do you no where is right? also what type spark plug should i be using and what type gas is best? what is a safe max rpm? thnx for any info
 
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paulie0735

Chief Petty Officer
Joined
Dec 6, 2005
Messages
463
Re: RANGER JACK PLATE QUESTION & PLUGS

Welcome to iboats, put simply your prop is too big. Your engine may or may not be to high but first things first. Your engine should be spinning to between 5500 and 6000 at wot. Proping it to this wot speed should sort your holeshot out. From there you can adjust the engine height for best all round performance. Max speed should not suffer as spinning a smaller prop faster will maintain your boat speed and be a lot kinder on the engine, they last much longer spinning fast and free than they do being loaded up with a prop that’s to big. Better fuel economy is a bonus. You will find lots of help available here to get it right, if you take the advice you will get it sorted very quickly. Good luck.
 
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moehuntin

Cadet
Joined
Mar 11, 2006
Messages
9
Re: RANGER JACK PLATE QUESTION & PLUGS

thanks for the input, but there is 4 other boats just like mine in our bass club and they all have 24 pitch rakers on them and one has a 26. i thought there may be a rule of thumb or something you could go by on the jack plate height. and they run 5400 rpm,s thanks
 
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Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: RANGER JACK PLATE QUESTION & PLUGS

Is your motor running properly?
 
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budsbud66

Petty Officer 2nd Class
Joined
Feb 25, 2006
Messages
105
Re: RANGER JACK PLATE QUESTION & PLUGS

Agreed, try a different prop. Its hard comparing to other people. alot of little things can make big differences. <br />I mean really, how many people can really have that identical setup? 87 150 G.T.'s arnt that common..
 
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moehuntin

Cadet
Joined
Mar 11, 2006
Messages
9
Re: RANGER JACK PLATE QUESTION & PLUGS

dhadley.... i did find out that the plugs were gapped at 21 thousands and boat mech told me they should be at 40 so im goin to try that and he said that that yr and size ranger came with that size prop. 24 pitch and also was told the center of prop should be at very lowest point of hull when motor is level. thank you
 
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moehuntin

Cadet
Joined
Mar 11, 2006
Messages
9
Re: RANGER JACK PLATE QUESTION & PLUGS

team starcraft.......those boats are very common here i guess cause there was 4 at our 1st fishing tourn last sat, same size same motor ect.<br />im hoping the plugs being gapped at 21 thousands had a lot to do with it not having much power out of the hole, i herd they are supposed to be 40 thousands. with ngk b9hs-10 it had b8hs in it at 21 thanks
 
LubeDude

LubeDude

Admiral
Joined
Oct 8, 2003
Messages
6,945
Re: RANGER JACK PLATE QUESTION & PLUGS

Are those #s you give with the engine trimmed out. Do you need a lesson in High performance boat operation? Have someone that has a boat like yours go with you and give you pointers.
 
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Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: RANGER JACK PLATE QUESTION & PLUGS

NO NGK'S!!!!<br /><br />Champions ONLY!!!
 
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moehuntin

Cadet
Joined
Mar 11, 2006
Messages
9
Re: RANGER JACK PLATE QUESTION & PLUGS

dhadley..... why do you say that? is that kinda just a ford or chevy thing or choc or vanilla or proof cause i was told nevr a champion, i put new plugs in tonight and when i started it ,it was idling like 2800 rpm compared to 1800 with the old pugs i had to turn down idling, so i no its gotta run better now. i lowered the jack plate a inch also and goin to give it a try and took off that dolphin tale ...thanks for your feed back dhadley moe
 
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budsbud66

Petty Officer 2nd Class
Joined
Feb 25, 2006
Messages
105
Re: RANGER JACK PLATE QUESTION & PLUGS

In my honest opinion i dont think 20k on plug gap will make a noticable difference.. spark is basicly spark.. if it were gapped so they were missing befor i could understand..<br /><br />NGK's are good plugs....... the ngk BRXEYA's made a huge difference over BRXES in my sled.. because of the variable temp difference.<br /><br />i still would recommend trying a prop with a slightly lower pitch.. Just try it...
 
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Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: RANGER JACK PLATE QUESTION & PLUGS

OMC carb'd motors were designed around Champion plugs. Just like Merc's and Yamaha's were designed around the characteristics of the NGK plugs. Some of the crossovers are not exact between the two brands.<br /><br />You can run NGK's but you need to go thru the jetting process and make sure it's right. Especially if you run something besides 87 octane. Just for kicks look up the price of pistons.<br /><br />The .020 gap will indeed have played a small part in your motor not running properly.
 
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moehuntin

Cadet
Joined
Mar 11, 2006
Messages
9
Re: RANGER JACK PLATE QUESTION & PLUGS

you guys are great! thanks im taking it to A MARINA TODAY a friend works there and we are goin to try some diff things ill let you no how it goes, thnks again, i went and bought some champions today, so now i got both hahaha ill get back with ya on the results see ya
 
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moehuntin

Cadet
Joined
Mar 11, 2006
Messages
9
Re: RANGER JACK PLATE QUESTION & PLUGS

hey!!! put new champion plugs in it gapped at 30 and lowered jack plate 2 inchs and set timeing that was just a lil off and it runs like a champ,come up good and planes out good. gps speed at 60 mph . thanks for the help !!
 
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moehuntin

Cadet
Joined
Mar 11, 2006
Messages
9
Re: RANGER JACK PLATE QUESTION & PLUGS

well.......... its still at 47-4800, witch is still confusing me but.... who knows the tach may be off. i mean it is 20 yrs old. and the top speed is way faster. i put a gps on it today so nxt time i go i can get a accurate speed, feels like atleast 60 mph, and its throwing a rooster tail about 20 ft long and about 2 ft off the water and its not coming from the prop, its coming out of water about 5 ft behind prop. i here thats the way you want to see it. thnx again hadley.
 
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