Prop pitch for heavy load

jph190 · **Posted:** Thu Aug 06, 2015 12:21 pm

Hi Everyone,

I recently acquired a 2000 Four Winns Horizon 190. It had been winterized and stored under a tree for six years when I got it. The work required to get it running reliably included replacing some wires and rebuilding the carburetor. Now it starts up and runs well.

When just my wife and I are out on the water, it accelerates and gets to top speed well. I haven't yet measured wide open throttle or top speed yet in this scenario.

When I have a group of 7 people onboard along with some beverages and such, I can't get it to go more than 10-15 mph tops. It gets up to that speed reasonably well but then I try to give it more gas and the engine bogs down.

The boat came with an aluminum propeller 14.25" diameter x 23" pitch. Is this pitch too high for the load? I have purchased a 14.5" diameter x 19" pitch propeller that I plan to use this weekend with a similar load. Looking for either some reassurance that this will help or suggestions on what else to try.

Thank you!!!

James

GottWhat · **Posted:** Thu Aug 06, 2015 12:31 pm

Welcome to the forums!

Do you have the 4.3GL or 5.0GL? Oddly, the 4.3GL stock prop has a larger pitch than the 5.0GL (23p vs 21p). With a light load what is your maximum RPM at WOT?

Going to a 19p might be best for you if you commonly have a heavy load and are not overly concerned with a light load maximum top speed.

GottWhat · **Posted:** Thu Aug 06, 2015 12:35 pm

Also, be sure to check out the "Fast Facts" for your boat here: http://www.fourwinns.com/customer-service-catalogs.aspx

jph190 · **Posted:** Thu Aug 06, 2015 12:49 pm

Hi GottWhat,

Thanks for replying so quickly! I have the 4.3GL. Don't know WOT RPMs yet but will check this weekend. I will typically be taking a group to a restaurant or wakeboarding and tubing. Top speed is not important as long as we can do 30+ with a group.

Do you think the bogging down I described makes sense as a symptom of being overpitched for the heavy load? Just want to make sure I shouldn't be looking at the engine.

Thanks,
James

GottWhat · **Posted:** Thu Aug 06, 2015 1:10 pm

jph190 wrote:

Hi GottWhat,

Thanks for replying so quickly! I have the 4.3GL. Don't know WOT RPMs yet but will check this weekend. I will typically be taking a group to a restaurant or wakeboarding and tubing. Top speed is not important as long as we can do 30+ with a group.

Do you think the bogging down I described makes sense as a symptom of being overpitched for the heavy load? Just want to make sure I shouldn't be looking at the engine.

Thanks,
James

It might be overpropped for your load as you state it runs great with just you and your wife. I would swap the prop before moving onto something else. If that doesn't fix it, move on to the next thing.

rpengr · **Posted:** Thu Aug 06, 2015 1:23 pm

jph190 wrote:

Do you think the bogging down I described makes sense as a symptom of being overpitched for the heavy load? Just want to make sure I shouldn't be looking at the engine.

Thanks,
James

No, I do not.

You have described that under this load, it accelerates OK up to a certain point in the throttle, the "bogs down" (loses some RPM?) when you push the throttle further. This is not a symptom of being overpropped. Most likely it is a symptom that you are not getting enough fuel through the carburetor jets at wide open throttle.

When it bogs down, does a little quick "pumping" of the throttle make it want to take off? That would be the accelerator pump adding extra fuel, and would confirm that you still have clogged jets. However, it might not work because the accelerator pump might not be working either.

You said that you rebuilt the carburetor, but maybe there is still a passageway that is clogged, or got clogged again with old fuel?

Ray

jph190 · **Posted:** Thu Aug 06, 2015 3:14 pm

Hi Ray,

Thanks for the reply. Yes, by bogging down I meant RPMs lower. The carb is actually a rebuild from marinecarburetors.com, basically brand new condition from what I can tell. I don't think the pumping helps, I pretty much can't get past 10-15 when weighted down no matter what I try.

Another piece of info in case its helpful.... I tested with 4 people on board instead of 7. With four people, I feel the engine struggling to get us past ~10 mph, but we can eventually climb out of that speed range and go as fast as we want. Almost as if that's the point where the boat's getting out of the water and planing so the resistance decreases. Again, with 7 people I can't get us past that speed no matter how delicately I finesse the throttle.

jph190 · **Posted:** Thu Aug 06, 2015 3:17 pm

I should clarify, with 7 people on board when I say it "gets up to that speed reasonably well" I mean it is possible to get up to that speed, not that it does so quickly.

rpengr · **Posted:** Thu Aug 06, 2015 3:22 pm

On my previous boat, I bought a carburetor from a company like that. They claimed it was pre-adjusted. I ended up having to put in the high speed jets from the old carburetor to get it running properly.

Ray

jph190 · **Posted:** Thu Aug 06, 2015 3:47 pm

Point taken, I'll take another look at the carb. Thank you!

Out of curiosity, has anyone else used a 14.25 x 23 prop with a group of 7 on a 19' bowrider with 190HP (or similar...)?

GottWhat · **Posted:** Thu Aug 06, 2015 3:58 pm

jph190 wrote:

Out of curiosity, has anyone else used a 14.25 x 23 prop with a group of 7 on a 19' bowrider with 190HP (or similar...)?

On our 2000 H180 w/5.0Gi (250hp) we went from an aftermarket SS 14.25 x 23p to a Michigan Wheel Apollo SS 14 x 21p and loved it. The issue with the 14.25 x 23p was it appeared to be over-propped with top speed coming at 4200-4400 RPM. The new prop had the same top speed but came around 4800 RPM, right where it was supposed to be. The hole-shot was much improved as well. Plus it was nice and shiny.

Surface Interval · **Posted:** Thu Aug 06, 2015 4:37 pm

Reducing prop pitch 2 inches will generally increase top end rpm by 300-400 rpm. 4 inches of pitch may be double that. Check your boat at top end with the outdrive trimmed up some to achieve maximum speed. See what the tach reads. If the same boat with a 4.3 has a 23" pitch prop and the 5.0 has a 21" pitch, it is because of the gear ratio in the outdrive. The gear ratio can vary from around 1.5 to 1 on up to about 2.3 to 1.

If your boat is struggling to get any speed with a load, it sounds more like an engine tuning problem to me.

Or...........

You might also look at just how heavily you are loaded, and what the weight rating is on the boat. If you are too heavy, or if the weight is concentrated toward the back, you would have problems just getting on plane. My old '95 190 Horizon had a weight rating of 1280 lbs. With that much weight in it, even the 5.0 EFI engine struggled to get it on plane, especially if the weight was aft. At that 10 to 15 mph you will probably only see around 3000 rpm max.

jph190 · **Posted:** Thu Aug 06, 2015 4:54 pm

GotWhatt, did you ever use the 14.25 x 23 with a group of 7 or 8 people? If so, any difficulty getting up to speed?

GottWhat · **Posted:** Thu Aug 06, 2015 7:07 pm

jph190 wrote:

GotWhatt, did you ever use the 14.25 x 23 with a group of 7 or 8 people? If so, any difficulty getting up to speed?

I did not have that many people, the most I had was 4 adults and 2 kids. Even with being over-propped the 250hp in a H180 made it alright, just ran below the recommended max RPM range. D

deafwish · **Posted:** Thu Aug 06, 2015 7:37 pm

You need more horsepower and torque!

Jokes aside, try moving the load more towards the bow.
Also consider a 4 blade prop, as this will give considerable stern lift - A feature a stern drive needs!

www.iFourWinns.com

Prop pitch for heavy load

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