198 motor upgrade

[559bigbass]

Was wondering if anyone has put a 250 pro xs on their 198?
what kinda of speed are u getting?
I have a 225 opti on mines and not getting the speed I like to get, 68-69Mph gps @ about 5300-5400rpm is what I’m getting, light load 1 person
full tournament load 2 people full tank 63-64mph gps @ about 5300rpm
running a stock tempest plus 25p prop, 10” champion hydraulic jackplate, motor has good compression on all 6

i also was thinking about a 225 pro xs , if I swap mines to that what y’all think will I gain any more speed?

[Lea]

A regular opti should be turning 5750 at wot. You might want to address that. I get 71.9 with regular 225 opti, half tank fuel, two big people,empty live wells and full gear load. I run a worked 26p tempest plus at 3,75 below pad. Sea level.

[Almag6]

check your tach for accuracy

[BillWoodard]

Fine tune you will love it

[STLBassBuster]

You could squeeze out a few more mph with a worked prop. Would probably pick up a couple mph going to a 225 Pro XS but a 198 could easily handle a 250.

[559bigbass]

check your tach for accuracy

I’m getting the reading from both Tach and smartcraft gauge they are the same reading

[559bigbass]

A regular opti should be turning 5750 at wot. You might want to address that. I get 71.9 with regular 225 opti, half tank fuel, two big people,empty live wells and full gear load. I run a worked 26p tempest plus at 3,75 below pad. Sea level.

What can cause motor to not run max rpm?

[Lea]

Could be several things. I am no expert, but throttle not fully opening, or prop to pad measurement needs adjustment are two possibilities. People who know better than I will be along, I am sure.

[STLBassBuster]

Opti’s are known for coil failures make sure you are getting spark on all six cylinders. A compression check would also be good to do.

[getfished]

Your prop may be underperforming. Just because it's shiny. Send it to Mark along with your data. Make sure your prop to pad is in the ballpark.

[grout-scout]

Something that’s not making sense, the rpms are basically the same loaded or unloaded? Do you have any kind of coating on the hull, power poles or talons? You in the higher elevations of CA or lower?

[559bigbass]

Could be several things. I am no expert, but throttle not fully opening, or prop to pad measurement needs adjustment are two possibilities. People who know better than I will be along, I am sure.

throttle checked opens up fully
i have a hydraulic jack plate so have tried adjusting motor height while driving

[559bigbass]

Opti’s are known for coil failures make sure you are getting spark on all six cylinders. A compression check would also be good to do.

haven’t check for spark but recently changed out spark plugs and all 6 looks to be burning , compression is 90lbs on 5 and one was around 80ish still within that 10% Range

[559bigbass]

Your prop may be underperforming. Just because it's shiny. Send it to Mark along with your data. Make sure your prop to pad is in the ballpark.

Been meaning to do that

[559bigbass]

Something that’s not making sense, the rpms are basically the same loaded or unloaded? Do you have any kind of coating on the hull, power poles or talons? You in the higher elevations of CA or lower?

that’s what I remember seeing on the smartcraft gauge, no power poles or talons, delta and tulloch is where I get the most speed out of the rig, higher elevation lakes 66-67mph is what I see 1 person light load same rpm

[grout-scout]

Your speeds aren’t all that far off, yes people here post speeds of their boats when they were brand new and they were faster; but most boats that have been used over the years tend to get slower. Your compression numbers aren’t all that great, but gauges read differently from each other. 65-69 are the speeds that I see posted on forums and Facebook and these boats don’t like the new heavy trolling motors either, they are bow weight sensitive.

[flashnyellow]

I agree with Grout. I did some searching on props/setups when I got my 198 in August and 65-70 mph was common. I have the 225 pro xs and best I've seen is 69.6 gps.

Ronnie

[Almag6]

that’s what I remember seeing on the smartcraft gauge, no power poles or talons, delta and tulloch is where I get the most speed out of the rig, higher elevation lakes 66-67mph is what I see 1 person light load same rpm

Run it and be happy. You're chasing 1-3mph and it just aint worth the time and effort

[pmgoffjr]

The last few mph would take trim extenders and getting your prop worked.
Unless you’re running at altitude then you’re ok.

[Ed R]

Originally Posted by 559bigbass
that’s what I remember seeing on the smartcraft gauge, no power poles or talons, delta and tulloch is where I get the most speed out of the rig, higher elevation lakes 66-67mph is what I see 1 person light load same rpm


"Originally Posted by Almag6" Run it and be happy. You're chasing 1-3mph and it just aint worth the time and effort

As Pat said, "put some trim extenders on, or 5* wedges". They do help.

Been chasing those mph for 13 years.............. Certainly could have used that money for a considerable down payment on a new Merc 8 cylinder four stroke.