Xpress H18 Performance

[Troy85]

I just purchased a 2009 Xpress H18 with Yamaha 115 4-Stroke.  I took it out the other day for a spin, just me, about 10 gallons of fuel and 3 batteries..  Running WOT the engine would only turn about 4900 RPMs and top speed was about 39mph.  I thought maybe the engine just needed a tune up, since I has sat idle for a few years.  I changed fuel filter, plugs, oil and lower unit oil and put fresh gas in the tank and some sea-foam.  

 

I take the boat out again after the above maintenance, this time its me, my brother, 3 batteries, and about 25 gallons of fuel.  The boat wouldn't even get on a plane, the engine was maxing out at about 3500 RPMs.  It would just plow thru the water with the bow high in the air, I tried adjusting trim, but could not get it up on plane.  I had my brother get out, and still the boat would not get on top of the water.  

 

Boat came with a 19 pitch prop, so we put a 15 pitch on there just to test.  With the 15 pitch prop, the boat would get on top of the water with both of us, but it did take longer than I think it should, the boat will plow thru the water before finally getting up on top of the water.  With the 15 pitch, we could get the engine to about 5700 WOT with an empty livewell, if the livewell was full it would only turn about 5400, max speed at this point is about 34mph.  

 

Basic specs: Xpress H18. Yamaha 115 4-stroke, 6" manual jackplate.

 

Now to my questions.

1.  What should be the normal performance for this boat with a 115?  Does anyone here have this same setup and maybe give me an idea of what to expect?  How is the hole shot?  What is average top speed?  

2.  If this in an engine issue, what could be the cause?  Engine seems to run smooth.

 

Any help is greatly appreciated.  I'm hoping its an engine issue, because if this the normal performance of this boat, I will be greatly disappointed.

 

Troy

[A-Jay]

Hello Troy and Welcome to Bass Resource 

Congrats on the new rig.

 

This might help.

http://yamahaoutboards.com/propellers/prop-shop-library

 

https://www.generalpropeller.com/pdf/QS_Yamaha.pdf

 

A-Jay

[Troy85]

Thanks for the links, I was just looking them over.  I'm thinking it may be some kind of engine issue, I just spoke with a dealer and the recommended a 17 pitch prop for that boat/motor combo.  They said the 15 pitch that we put on as a test was way under propped.  Which makes me think, if the motor is under propped, shouldn't the engine not have trouble reaching max RPM at WOT?  Assuming the engine is running as it should.

 

 

[WRB]

H16 or H18, title says X18 and specs ? Not all that familiar with your boat , however most bass boats in 17'.5 to 18' with 115 hp run 19 pitch 3 blade SST without any problems, 17" P would be the minimum I believe. No reason to fill the livewells when trying to trouble shoot. Sounds like you need to check the power packs, take everything you don't need out of the boat including a full tank of gas to reduce some weight during the prop testing phase?

Tom

PS, max hp for H18 is 150, I see they offer this boat with 115 hp option.

 

[Troy85]

Sorry.  The specs was a typo its H18, I corrected it.  The stock prop was a 19 pitch, but it wouldn't even get on plane this morning.  It would only hit about 3500 while plowing thru the water.  The 15 pitch did allow us to plane, but it seemed painfully slow and still could only go about 33-34mph.  We didn't fill the livewells to trouble shoot, the bass started biting

 

 

[fishnkamp]

There has been a lot of trouble with contamination by damage from ethanol fuel  The older fuel lines are well documented as deteriorating and clogging things downstream as well as shrinking the lining inside.  There is a quick and simple way to test. Go to your local boat dealer. Purchase about 10 feet of new ethanol resistant fuel line.  Also purchase a new primer bulb and clamps.  Make a temporary line to go from a 5 gallon gas can filled with new fuel to the place the existing primer bulb is. Place the tank on the cockpit floor. Make sure you make a piece to match the existing piece that goes from the primer bulb to the engine. Now go to the ramp and launch the boat.  Prime the new bulb up . Go test run the boat . if it runs right than replace the old line from the boats internal tank to the new primer bulb. If the engine was starving for fuel this will help. I had to do this repair on my 2010 Lowe and I ran Startron since it was new. I would also replace the new fuel filter as well. Sorry, I just do not trust it since it could be full of the gunk again. I would replace it again in order to make my test with the best fuel system possible.  I have seen this drive guys crazy before.

[Troy85]

I will have to try this, thanks for the info.

[Al Wolbach]

I don't believe any Yamaha outboards have had a problem with fuel line ethanol problems. Yamaha fuel lines are compatible and always have been, at least mine are, back to 1998. I would suggest going to *** and check the express boat forum for advice. 

Maybe if you pm me I can give you the website, apparently it's blocked

[WRB]

J Francho knows Xpres boats, maybe John will commit.

Tom

[WIGuide]

I would get the motor checked first before you start messing with setup. Throwing time and money at setups only to find out that there was an issue with the motor to begin with and then you get to start the process all over again, it's not worth it. Just get it checked out first.

[fishnkamp]

I have read a few Yamahas that did have the fuel line issue causing it to collapse internally. I have also read about issues with tank vent issues occurring. Every manufacturer can have a problem with a primer bulb and its internal valves.  I suggested a simple way to eliminate the entire fuel tank to engine components.If the engine runs the same, then the problem must be engine related.  If the engine runs right then you have the parts to replace the entire system.  Last April I spent 10 days on Dale Hollow. The mechanic at the resort and marina said he fixes those issues on all brands regularly.  His personal favorite parts to use were the primer bulbs that Johnson made and some aftermarket blue colored ethanol rated fuel line he stocked by the box loads.    

[J Francho]

I had a 22p Laser II on my H18 with a 115 ELPTO Merc.  Fully loaded, around 50 mph.  No load, low fuel, 55.

[Troy85]

I maxed out at 39 with just me and low fuel, with the 19P prop, that was going with the wind, against the wind it was about 37.  I brought the boat to the shop this morning to have the engine checked out, hopefully they have a chance to look at it today.  The suspense is killin me.

[Troy85]

The shop ran a diagnostic on the engine and found that the fuel injector on number 3 cylinder isn't opening.  I had them check all the fuel lines between the tank and the engine, they said the lines seemed ok.  The mechanic is going to pull and clean then test all the injectors, and pull apart and clean/replace filters inside the VST tank. He said it should be done not later than Wednesday, but he may have it done this afternoon.  I'll take it out and run it again and let yall know how it goes.  Thanks for all your help so far.

 

Troy

[WRB]

You are going to need a higher pitch prop!

Tom

[Troy85]

I left the 19 pitch inside the boat when I dropped it off. The mechanic said he would take the 15 pitch off, and put the original 19 pitch back on for me.  He said that motor would have  hit the rev limiter with that 15 pitch, if it had been firing on all 4 cylinders.

[fishnkamp]

Glad the found the problem. That should be a good motor for you.  Make sure to pick up some fuel treatment before filling it up. I have been using the Star Tron since my boat was new.  Even if you are able to avoid ethanol fuel, there is no way guarantee how fresh the fuel we get is.  

[Troy85]

Boat seems to be running great now.  Took it out yesterday, it ran 46 with me and 1 passenger.  It seems to be running like a champ.  Now if only the weekend would hurry up and get here!  Thanks for all the info and help everyone.

 

Troy

[J Francho]

That sounds more like it with that prop.  Enjoy!

[WIGuide]

Glad to hear it's back up and running like it's supposed to!

[Catt]

Did the mechanic guarantee it would catch fish?

[J Francho]

3 minutes ago, Catt said:

Did the mechanic guarantee it would catch fish?

 

It's an Xpress!  That is implied!

[Troy85]

Haha...I should have paid him extra so he could guarantee limits.