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RPM Sync with Cruise Assist?

Discussion in 'Yamaha AR240, SX240, 242 Limited / S / X/ E-Series' started by AZ Native, Apr 22, 2018.

  1. AZ Native

    AZ Native Jet Boat Lover

    Messages:
    187
    Location:
    Phoenix, Arizona 85044
    Ratings:
    +195 / 7
    Boat Make:
    Yamaha
    Year:
    2013
    Boat Model:
    Limited S
    Boat Length:
    24
    This is driving me crazy and I can't find a solid answer searching so here goes.

    Does Cruise Assist on a twin engine boat synchronize the throttle RPM between the two when engaged? It's not addressed in the operating manual and I can't find the topic anywhere else.

    I was playing with it at the lake yesterday and I can't tell for sure. One time it seemed to sync the engines and the annoying pulsing drone went away. Other times it didn't sync the engine RPM's when engaged. Seems to me that cruise control with engines out of sync is kind of annoying. Am I doing something wrong or is there something I don't understand.
     
  2. Chris Jordan

    Chris Jordan Active Member

    Messages:
    15
    Location:
    Maitland, Florida
    Ratings:
    +5 / 0
    Boat Make:
    Yamaha
    Year:
    2018
    Boat Model:
    AR
    Boat Length:
    24
    Im surprised no one replied to your question yet. The Cruise Assist does not automatically sync your engines/rpms. I get up to the speed I want and manually get the throttles/rpms as close as possible to match, then hit Cruise Assist. If the rpms are off enough to create the annoying pulse, I simply raise or lower one of the throttles until it's matching the rpms of the other, then hit Cruise Assist again.
    Sounds like a lot of work but you get good at it after a few times.

    Thankfully the No Wake modes do keep the rpms synced so you don't have to deal with them manually
     
  3. AZ Native

    AZ Native Jet Boat Lover

    Messages:
    187
    Location:
    Phoenix, Arizona 85044
    Ratings:
    +195 / 7
    Boat Make:
    Yamaha
    Year:
    2013
    Boat Model:
    Limited S
    Boat Length:
    24
    @Chris Jordan Thanks for the input. I used cruise a lot on a recent Lake Powell trip driving 20 to 30 miles at a time and used it a lot while pulling my son wake boarding. I finally came to the same conclusion you did, but on occasion if the RPM's are close enough. engaging cruise seemed to tighten up the sync even more. Maybe it's my imagination. My bigger problem is really the Port engine at WOT is at least 700 or more RPM below the top end of the Starboard engine. At 3,600 feet I was only able to get about 6,100 RPM out of the Port side while the Starboard could produce closer to 7,000. I had the same problem with 2005 AR I recently replaced. This is a very frustrating experience. I've adjusted the throttles, replaced plugs, etc. I think I'll start another thread to see how common a problem this is.
     
  4. swatski

    swatski Jetboaters Fleet Admiral

    Messages:
    8,100
    Location:
    Saint Louis, MO
    Ratings:
    +8,721 / 132
    Boat Make:
    Yamaha
    Year:
    2016
    Boat Model:
    AR
    Boat Length:
    24
    The Ridesteady/Hydrophase! Closest thing to fly-by-wire "single lever control" of E-series 2015+ Connext boats. It is fantastic and works surprisingly well (as an electronic cruize control and in synchronizing the throttles across the entire RPM range). The system has no servos or anything mechanical, and it will work in any Yamaha with an APS (accelerator position sensor) - any 210 and any 2010+ 240.
    It would be my first mod in any non E-series boat.

    --
     
  5. swatski

    swatski Jetboaters Fleet Admiral

    Messages:
    8,100
    Location:
    Saint Louis, MO
    Ratings:
    +8,721 / 132
    Boat Make:
    Yamaha
    Year:
    2016
    Boat Model:
    AR
    Boat Length:
    24
    That's unusual. Typically the STRBD is slower. Maybe your impellers are switched? I think the PORT has notches on the impeller's "neck", you could see those through the intakes (looking back from under the boat).

    --
     
  6. AZ Native

    AZ Native Jet Boat Lover

    Messages:
    187
    Location:
    Phoenix, Arizona 85044
    Ratings:
    +195 / 7
    Boat Make:
    Yamaha
    Year:
    2013
    Boat Model:
    Limited S
    Boat Length:
    24
    I removed both air filters and ran the boat all day yesterday. The port engine performed much better. It ran 7,000 rpm compared to about 7,200 for the Starboard engine with 6 passengers. I was boating at an altitude of 1,700 feet compared to Lake Powell at 3,600 feet. There was a little oil in the intake tube of the Port engine so I assume the Port filter has oil on it, but it’s really not obvious. I assumed with the filter boxes on these newer engines being remoted from the intake (unlike the MR1’s) oil couldn’t get in the filters. The Starboard engine is dry as a bone being so far remoted from the intake.

    I still have to pull the starboard throttle back quite a bit at WOT to match the engines. I’m thinking about leaving the filters out permenately. The oil on the dipsticks are above the 2nd hole for both engines, telling me they are a little overfilled. Once again I thought high oil level was only a problem with the older MR1 engines.
     
  7. swatski

    swatski Jetboaters Fleet Admiral

    Messages:
    8,100
    Location:
    Saint Louis, MO
    Ratings:
    +8,721 / 132
    Boat Make:
    Yamaha
    Year:
    2016
    Boat Model:
    AR
    Boat Length:
    24
    The oil vapors recaptured in a 1.8 bypass the air filter, unlike the MR-1.

    You should definitely consider a ribbon delete, that is the first mod at altitude
    There are many posts on this, here is one, just to give you an idea. It is 100% worth doing in your situation since you are not even close to the electronic rev limiter threshold (of ~7,800-7,900 RPM). Should gain you some 200-300RPM at WOT, with or without the intake "kit". Running without a filter usually does not do much of anything in 1.8 N/As (maybe 50RPM?), so you filters must have been really clogged up...
    https://jetboaters.net/threads/yes-...install-not-the-worthiness.13144/#post-228975

    --
     
  8. AZ Native

    AZ Native Jet Boat Lover

    Messages:
    187
    Location:
    Phoenix, Arizona 85044
    Ratings:
    +195 / 7
    Boat Make:
    Yamaha
    Year:
    2013
    Boat Model:
    Limited S
    Boat Length:
    24
    @swatski Thanks for the link to the Ribbon Delete Thread. Doing my research it looks like I have the complicated throttle body version on my 2013. So I'm going to have to deal with the bolts on the Throttle Body, and the Bolts on the spacer, just to get to the Ribbon. Do I also need to delete the Holder (item 19 in the exploded view)? Seems like I need to leave it so the air flow doesn't get disrupted.
    2013 Throttle Body.PNG
     
  9. swatski

    swatski Jetboaters Fleet Admiral

    Messages:
    8,100
    Location:
    Saint Louis, MO
    Ratings:
    +8,721 / 132
    Boat Make:
    Yamaha
    Year:
    2016
    Boat Model:
    AR
    Boat Length:
    24
    Yes, delete the rubber gasket! Left behind - it will get sucked into the intakes... bad things happen then.

    There should be no complications pulling the ribbons out in your N/A 1.8s, other than the size of the ribbon varies (there are two different sizes) - so if you want to get the "kit" with the spacers (those are cheap at ~$40 each) make sure you give the exact MY.
    In SC (SHO, SVHO) the entire intake manifold needs to be pulled off - that is not the case with twin boat 1.8s.

    The spacer rings in the kit will replace the ribbons and the rubber gaskets. It is questionable if those actually help the air flow and/or are necessary. Some just remove the ribbons and rubber gaskets and are done. I have never seen any hard data indicating the spacers help, but they can not hurt (if correct size is used).

    You already know how to get the air filters out, no need to unbolt them as they slide out off the rubber holders.
    Let me know if you need more pics of part numbers for anythign!
    --
     
  10. AZ Native

    AZ Native Jet Boat Lover

    Messages:
    187
    Location:
    Phoenix, Arizona 85044
    Ratings:
    +195 / 7
    Boat Make:
    Yamaha
    Year:
    2013
    Boat Model:
    Limited S
    Boat Length:
    24
    I ordered the spacers. Might as well install them while I have the Throttle Body's apart. The Riva spacers are meant to insert into the existing rubber gasket that ribbon comes out of, then just reinsert them The same model spacer apparently works with all 2013 and newer 1.8s. I'll take the snorkels out before I insert new filters. I will never be boating at sea level, so I appreciate this option for higher altitudes which seriously impede performance with these engines. I guess the fuel injection on these motors doesn't work the same way as a car which wouldn't experience power loss at high altitudes. A couple of references for the benefit of others:
    Riva Spacer.PNG Riva Spacer Install.PNG
     
    • Like Like x 1
  11. swatski

    swatski Jetboaters Fleet Admiral

    Messages:
    8,100
    Location:
    Saint Louis, MO
    Ratings:
    +8,721 / 132
    Boat Make:
    Yamaha
    Year:
    2016
    Boat Model:
    AR
    Boat Length:
    24
    That is correct, I misspoke above.

    Ribbon delete should help for sure, the mod recommended for altitude. I believe that is what @Williamsone46 does with his Lake Powell Yamahas, after that its to impeller repitch.

    --
     
    • Like Like x 1

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