1989 18-4 champion dual console with 175merc top speed and rpm range

[ksw390]

i baught this boat 2 years ago fished it last summer 3 times a week motor sounds great and idels great just wouldnt turn the rpms i i think it should have so i took it to the shop and they said the timming was way off but saposevly fixed the isue. i took it right to the water and im getting 5300 or 5400 with 23 pitch laserII at 56 mph on gps the boat is a 18-4 champion same year as motor i also tryed a 21 pich prop i reached about 5400-5500 rpm at the same speed 56 on gps so i tryed 25 pitch prop got 55 mph on gps and 5000. i do know this boat motor combo is capable of 65-67 mph cause i owned the exact twin to this boat a few years ago and i could turn 6000 with that 175 at 67mph any body have any ideas

i posted this in the mercury forum and they told me to come post it here as well thinking maybe someone else might have had the same isue

here us a little more info on what the shop told me and what they did. they hooked the boat up to the dino and opened it up to WOT and tuned the dino to the rpm i told them i was getting. he checked the timming and found it to be off quite a bit, so he adjusted it and wow did she come alive i gained alot more torque and more rpm. acording to the dino. he advised me that he would disconect the timming advance module and set the timming manually so i had them do that. he alo said that he could still advance the throttle a bit more if i ever needed to since we were no longer using the advance module. so now that i am running a 25 pich prop i am not getting the rpms i need to make the boat preform the way i would like so should i just take it back to the shop and have them hook it back up the dino and re tune it or is there somthing else i can try before i go back to the shop.....

[BILLY]

Injector flooding?????

[ribbit_man]

Glad you took my advise and joined us on the Champion forum. Welcome!!!

Pat Goff is the resident GURU on Champion setups and should be along shortly unless he is chasing rat reds. You can take his advise to the bank as he used to be a "test pilot" for the original Champion boat company in Mt. Home. Knows his stuff.

[ChampioNman]

I'd make sure the throttle plates are opening fully, and check your prop to pad distance. I'd think you could spin a 21 to the moon! Something is amiss here.

[ronb]

I'm sorry your having this problem but, I'm going to follow this thread as I am having the same proble. I'm hoping mione is fixed..I had the throttle cable adjusted and pad/prop heighth checked this week. I am going to test it out this weekend. I was only getting 4200 rpms with a SCR 184,Mariner 175 EFI and 24 pitch Tempest Plus prop

[ksw390]

for ronb

i can spin a 21 now no prob but 21 pich is no where nere enough prop. this thing should spin the 23 at 6000 if i wanted to. i always run my boats at 5800 WOT fully trimmed but i cant get near that with my 23 now i can only turn 5500


when i first baught this thing it would only turn 46 with the 23 just like the prob your havin now and the shop found the timming to be way off at WOT he said somthing about the timming advance module dont kick it till a sertain rpm and that my timing being off wasnt letting the motor turn enough rpms for the advance module to kick in so you could have a bad avance module or your timming could just be off just like mine was. the shop disconected my advance modual and set the timming permenit you should look at that

[ksw390]

as for my setup prop to pad not sure what your saying but exactly but i think its this

center of my prop is exactly 3" below my pad my throttle is opening all the way i have great compretion good spark everything has been checked and checked out ok as far as i can check..

i am having another thought about maybe trying some boysen reeds im sure mine are factory so that would have to be a improvement what do you guys think about that

ill also post a pic of the boat just got it back from having it repainted it looks great.

[ksw390]

dont do my any good to look nice if i aint happy with the way it runs

[tracy shannon]

i had a 85 184 sc same set up i could turn a 24 predator beast 4blade 6000 rpm never had a gps on but guy i sold it too says 70 mph + i think you need a 24p 3 blade and check your rpm gauge but something is definitly a miss somewhere you should be close to 5800 -6000 rpm depending on how heavy of a load you are caring

[siskiyoucrash]

Both of you could have power pack issues,,they can come and go, will usually drop the rpm on this combo to around 4200.

[ChampioNman]

You could have a wet hull too. Take it to a truck stop and weigh it.

[ribbit_man]

How much should this rig weight?

[Lea]

I don't have the 89 one, but brochures from 90 to 94 show anywhere from 1200-1385 hull weight alone. Never have understood why the difference...

Just read your (ksw390) post in the Merc forum. You say you just installed a 10" JP. Not sure about 10" on a 184, but our guys will know...

[ronb]

This last tuesday I had my boat in the shop. I had the mechanic check my throttle cable I had just installed. he said he adjusted my throttle about 1/4 inch or more...that took care of my high rpms at idle. I also had him check my motor to pad ratio...I must have measured wrong before because my prop spine is 3.5 inches below pad.

My hull weight is listed at 1200 lbs.

I just got back from Indian lake in Ohio and things were much better...I had the motor all the way down when I stomped the pedal and the boat came out of the hole as fast as I have ever seen one do and I was getting right at 60 mph gps. That was with a full tank of gas, three batteries, 480 lbs of men, and full tourny load of rods,gear etc.
Is that the speed I can expect? I keep reading that my boat setup is pretty common for the year and model I have but, everyone is sayng they are getting 65+ mph. Are the speeds everyone has been talking about been in a tourny ready rig with two guys or just in a stripped down boat with one man aboard?
I will admit that I was so excited about running almost 20 mph faster than last week that I forgot to look at rpms ..I was watching my gps and water pres guage.

KSW390..that boat looks great! Did you get new seats or recover yours?

Ron

[WaYoop]

Glad you got it figured out. You are probably at about the max speed with your rig with a full load.

[ksw390]

to ronb id realy like to know what rps you were turning im still only getting 5000 but i do have a 25 pich prop im thinking about going back to the 23

and by the way on the seats i had them recovered along with my but seat and a new seat for the back it cost me 364.50 i was verry happy with the final look of them

[ksw390]

how do i check the high side of my stator to make sure its putting out all the power it should

[gfd403]

IM Sent

[Smokey Joe]

Both of you could have power pack issues,,they can come and go, will usually drop the rpm on this combo to around 4200.

listen to this man and check your spark using a 7/16 gap spark checker.

[Smokey Joe]

I was running 5500 rpm and 59 mph gps and took it in to my buddies shop and found out I was running on 5 cyl.
the engine im running is a Johnson GT 150 with a 22 P Raker.
I should get it back on the water this coming week lets see what it can do now !