Ribbon Delete Kit — Install Guide

GT40 Marine | SKU GT40-SD-RDK-SD300 | Ribbon Delete Kit with Block-Off Plates | Rev 1.0 — 2026-05-24

Fitment

|---|---|---|---|

Not for: Spark, 1503 4-TEC. Confirm engine code (1630 ACE) before install. The ribbon refers to the factory exhaust silencer "ribbon" / waterbox flap assembly that adds backpressure and bypasses sound at low RPM. Removing it improves exhaust flow and exposes the true exhaust note — required modification for any Stage 2+ tune.

In the Box

(1) GT40 ribbon-delete block-off plate, billet aluminum, anodized black
(1) Block-off plate gasket, marine-grade, fire-rated
(1) 3-1/8" hole saw (for cutting the exhaust port if not already opened)
(1) Arbor and pilot drill bit for the hole saw
(4) M8 × 25 mm SHCS — block-off mounting
(4) M8 stainless flat washers
(4) M8 nylon-insert lock nuts
(1) High-temperature exhaust sealant tube, 4 oz
(1) Cleaning solvent wipes (for prep surface)
(1) GT40 product registration card
(1) This guide

Verify all components present before starting. Missing parts: support@gt40marine.com.

Tools Required

10 mm / 13 mm sockets + ratchet, 3/8" drive
T25 + T30 Torx drivers
5 mm + 6 mm hex (Allen) keys
1/4" drive torque wrench, 5–25 Nm range
Drill (corded preferred for the hole saw cut), 1/2" chuck
Hole saw arbor (provided in kit)
Center punch
Shop towels
Marine-grade exhaust sealant applicator (small brush)
Flashlight or headlamp

Safety

Read in full before starting.

Battery disconnected for the duration of the install.
Cold engine only. Exhaust components retain heat for over an hour after operation.
Eye protection mandatory during the hole saw cut. Aluminum shavings are sharp.
Hand protection when handling the exhaust manifold — sharp edges, residual carbon deposits.
No smoking / open flame. Exhaust sealant fumes are flammable until cured.
Hearing protection during hole saw operation.

If you are not comfortable with PWC exhaust system work, take the install to a certified marine technician.

Pre-Install Checklist

[ ] Watercraft on stable trailer or stand
[ ] Battery negative disconnected and isolated
[ ] Engine bay clean and dry
[ ] Existing ribbon-port status verified — some 230HP craft ship from BRP without the port pre-cut; this kit includes the 3-1/8" hole saw for those cases
[ ] Hole saw assembled to the arbor with the pilot bit centered
[ ] Exhaust sealant tube at room temperature for proper viscosity

Step-by-Step Install

Step 1 — Access the Engine Bay and Locate the Ribbon Port

Remove the seat and engine bay top hatch. On RXP-X / RXT-X, also lift the rear storage bin.

Locate the factory exhaust manifold on the inboard engine bay sidewall. The ribbon port is on the outboard side of the manifold, midway between the cylinder head exhaust takeoff and the waterbox inlet. On 300HP craft, the port is typically pre-cut by BRP and capped with a thin metal cover. On 230HP craft, the port may be pre-drilled but uncut, or completely closed.

Disconnect the battery negative terminal.

Step 2 — Identify Port Status

Inspect the manifold at the ribbon-port location:

Pre-cut + capped: factory configuration on most 300HP. Remove the existing cap (4 small fasteners, 8 mm) and discard. Skip to Step 4.
Pre-drilled but uncut: factory configuration on some 230HP. The 3-1/8" port is marked but not opened. Proceed to Step 3 to cut the port.
Completely closed: rare, mostly on early-year 230HP. The port location is marked from inside the manifold but no exterior preparation. Use a center punch to mark the port center, then proceed to Step 3.

Step 3 — Cut the Ribbon Port (if needed)

Skip this step if the port is already pre-cut.

Position the manifold so the port location is accessible and shavings will fall away from the engine
Place a clean shop towel over the engine bay to catch shavings
Apply the pilot drill to the center punch mark, drill a pilot hole through the manifold wall (slow speed, light pressure)
Assemble the 3-1/8" hole saw to the pilot
Cut the port at low speed (300-500 RPM), applying steady pressure — do not force
Remove the hole saw and clean the bore with a wire brush + shop towel
Deburr the inside edge of the new port with a small file (the aluminum manifold wall is 5 mm thick — leave a clean 90-degree edge)
Vacuum all shavings from the engine bay before proceeding

Step 4 — Prepare the Block-Off Mounting Surface

Wipe the port flange with the supplied cleaning solvent wipe
Verify the flange is flat — no carbon deposits, no surface scoring
Light scuff with 220-grit sandpaper if any surface contamination
Final wipe with a clean solvent wipe
Allow 60 seconds for full solvent evaporation before sealant application

Step 5 — Install the Block-Off Plate

Apply a thin even bead of the supplied high-temperature exhaust sealant to the manifold-side face of the supplied gasket
Position the gasket on the port flange, aligning the bolt holes
Apply a second thin bead of sealant to the gasket's outboard face
Position the GT40 block-off plate over the gasket, aligning the 4 bolt holes
Thread the 4 supplied M8 × 25 mm SHCS through the plate with flat washers
Thread the M8 lock nuts onto the back side of the manifold flange (some hulls require a long socket extension to reach)
Snug all 4 bolts in a cross pattern (1-3-2-4 sequence)
Torque all 4 bolts to 22 Nm (16 ft-lb) in two passes — first pass at 12 Nm, second pass at 22 Nm
Wipe any sealant squeeze-out with a clean rag

Step 6 — Allow Sealant Cure Time

The exhaust sealant requires a minimum of 2 hours cure time before engine start. Do not skip — premature start can blow uncured sealant out of the joint.

If you can wait overnight, recommended. Maximum cure strength at 24 hours.

Step 7 — Reassembly and First Start

After cure:

Walk the engine bay — every fastener, every clamp
Confirm no tools or hardware remaining
Reconnect the battery negative terminal — torque to 10 Nm (89 in-lb)
Replace the engine bay hatch, storage bin, seat
Start the engine on the trailer with the cooling hose connected
Idle for 60 seconds — listen for any exhaust leak (sharp ticking sound, gas smell)
Bring the engine briefly to 3000 RPM — confirm the new exhaust note is louder and more open than stock (this is the intended result)
Visually inspect the block-off plate for any sealant migration or weeping
Scan with BUDS or compatible OBD diagnostic — no fault codes (the ribbon delete does not trigger any factory codes, but it's worth verifying)

If clean: install complete.

Post-Install

Break-In

First water test should run a conservative throttle profile for the first 5 minutes to allow the sealant final cure cycle under operating temperature. After 5 minutes at part throttle, full throttle pulls are safe.

The exhaust note will be noticeably louder above 4000 RPM. This is the intended result — the ribbon was a sound-attenuating bypass, and its removal exposes the true exhaust character.

Tuning

The ribbon delete is mechanical-only and does not require an ECU tune for fitment.

For Stage 2 and higher builds, the ribbon delete is a prerequisite — Stage 2+ tunes assume the additional exhaust flow and will run lean / underperform with the factory ribbon in place.

Service

Inspect the block-off plate every 50 run hours for any sealant weep
Re-torque the 4 M8 SHCS at the first 10-hour service to 22 Nm (initial gasket compression)
After 200 hours, plan a full sealant inspection — if any weeping is visible, plan a sealant refresh at next service

Troubleshooting

| Symptom | Likely Cause | Fix |

|---|---|---|

| Exhaust gas smell in engine bay | Block-off plate leak | Stop operation, retorque to 22 Nm, monitor; re-seal if leak persists |

| Sharp ticking sound at exhaust port | Gasket failure | Drain, remove plate, replace gasket + sealant, reinstall |

| Block-off plate visibly migrated | Bolts under-torqued | Retorque all 4 to 22 Nm — if any bolt threads stripped, contact support for replacement |

| Engine performance unchanged | Existing ribbon was already removed | Some craft ship from BRP without the ribbon — your install adds confidence but no performance change |

| Excessive water in exhaust note | Cooling system overflow into exhaust | Inspect cooling system, separate issue from this kit |

| Check Engine light post-install | Unrelated to ribbon delete | Scan codes — ribbon delete does not trigger factory codes |

If symptoms persist after the checks above, contact GT40 Marine support before further operation.

Torque Reference Summary

| Fastener | Torque |

|---|---|

| Block-off plate M8 SHCS (all 4) | 22 Nm / 16 ft-lb |

| Battery negative terminal | 10 Nm / 89 in-lb |

All torque values nominal — refer to current Sea-Doo factory service manual for any conflicting OEM specifications.

Warranty

GT40 Marine warrants this kit free from defects in materials and workmanship for ninety (90) days from date of purchase. Warranty covers replacement of defective GT40-supplied components. Warranty does not cover:

Damage from improper installation (including cutting the wrong manifold port)
Damage from premature engine start before full sealant cure
Damage from operation with the block-off plate not properly torqued
Use on craft outside the listed fitment matrix

To submit a warranty claim: email support@gt40marine.com with order number, photographs of the installed kit, and a description of the failure mode. Response within two business days.

Support

Email: support@gt40marine.com
Site: gt40marine.com
Install help: include the GT40 SKU above and your hull serial number in any support correspondence

Built in the United States. Designed for buyers who want the best.