If your boat fires right up warm but cranks forever cold, the issue is fuel delivery, glow plugs, or compression — and it almost always gets worse over the season.
What to Check
1
Glow plugs (diesel)
A single failed glow plug makes a 4-cylinder cold start brutal. Cheap part, easy test.
2
Lift pump / fuel priming
Air in the fuel line means the engine has to crank long enough to re-prime. Inspect the lift pump and check for leaks at fittings.
3
Cold-start enrichment (gas)
Failed choke, sticky enrichment valve, or weak fuel pump on carbureted engines.
4
Compression
Aging engines lose compression on cold cylinders. A 5-minute compression test tells you everything.
When to Call Us
If you've replaced glow plugs and primed the fuel and it still cranks long, get a compression test before winter — cold mornings only get worse.