Sierra 18-5602 Outboard StarterReplacement Mercury Outboard Starter fits 35-40 HP, 2 Cyl. and 50 HP 4 Cyl. models. Sierra replacement outboard starters are manufactured to meet or exceed OEM requirements. Tooth Count: 10; Fits 35-40 HP, 2 cyl. & 50 HP 4 cyl. models; Interchangeable with: Arco; 5374; Mallory; 9-15024; Mercury Marine; 50-44369A1; 50-58788A3; 50-60315; 50-65436; 50-67341; MES; S2032M;