Williamsone46
Jetboaters Captain
- Messages
- 980
- Reaction score
- 954
- Points
- 247
- Location
- Lehi, UT
- Boat Make
- Yamaha
- Year
- 2024
- Boat Model
- 255XD
- Boat Length
- 25
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Is that legal? I thought there was a requirement to have a spark arrester on inboard boat engines. Maybe I'm thinking of something else...The second and third picture show the spark arrester that was removed.
You can install an aftermarket air filter that also acts as a flame arrestor to comply with state/fed law.Is that legal? I thought there was a requirement to have a spark arrester on inboard boat engines. Maybe I'm thinking of something else...
No they are not. 1.8l 2015 intake manifold is different than 2016, with different ribbon diameter.I am not certain but I believe that All normally aspirated 1.8 liter Yamaha marine engines use the Same intake modification / part number. I recall that someone here discovered that the supercharged engines use a different part number because the size is differentt/bigger for the supercharged engines.
@Ronnie I'm glad you took my advice and looked up the parts numbers for specific models using suppliers microfiche.No they are not. 1.8l 2015 intake manifold is different than 2016, with different ribbon diameter.
@Nick Hughes I would check the part numbers (throttle assembly, ribbon) of the exact boat model number in one of the microfiche suppliers.
I don't think there is a difference for CARB models, but you will find that in parts, too.
@Greg M There is a (very) strong consensus on the benefits of removing the ribbon (in 1.8l engines), but I am not so sure there is a consensus on any benefits of replacing it with the RIVA ring. Some put it in, some don't. I don't think there is data out there showing additional benefits of inserting the ring, on top of removing the ribbon. Please correct me if I'm wrong.Flat out removal of the stock arrestor and not putting anything in will give you some gain but then you kill the flow (turbulence again and it matters!) when the lip the arrestor was sitting in (see his third pic) comes into play and kills the laminar flow.
Unless I have this all wrong, and PLEASE let me know if i do, and Im basing this on Williansone46 pics, the ribbons are made into or attached to the throttle body insert? (item 17 on the exploded view). If you can just take out the ribbon, youre golden and know it for a fact. If you have to remove the insert itself to get the ribbons out (they are attached in a way that you cant remove them without removing the entire insert) you have to put something in that void so your airflow laminar matches the throttle body, otherwise the lip the insert is riding on will ruin anything you gained by removing the insert.@Greg M There is a (very) strong consensus on the benefits of removing the ribbon (in 1.8l engines), but I am not so sure there is a consensus on any benefits of replacing it with the RIVA ring. Some put it in, some don't. I don't think there is data out there showing additional benefits of inserting the ring, on top of removing the ribbon. Please correct me if I'm wrong.
Of course you are right, in theory, about the air flow. However, when it comes to these engines and pumps, things that make theoretical sense rarely work in practice.
It is all a game of figuring out what the limiting factors are.
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