Yanmar 2GM20 – Squeaks on cold start

A Yanmar 2GM20 owner asked...
I have a Yanmar 2GM20 in my boat and it’s started squealing at start (especially cold start) and there is a delay in water exiting the exhaust. Squealing stops and then water flows.

Next time at boat I’ll service it but is this likely a belt, new impeller needed, or bearing?

… and the owners’ group said…

Start by checking the belt tension on the raw water pump. You should be checking it regularly when you check the oils anyway …. and adjust as required.

D Jones, Brighton.

you can always isolate the Sound by holding a length of garden hose to your ear and carefully pointing it in the direction of the different areas that might be squeaking to help determine a little bit more clearly where the offending squeak might be squeaking from

G Walsh.

It is most likely the belt slipping. It may just need adjusting. It also could be the water pump, bearings, or your alternator bearings. Start be tightening the the belt and then take it one step at the time. The impeller does not cause the problem, it would just destroy itself.

H Erhard, Philippines.

A smart skipper learns from the lessons of others.

In our Yanmar GM Series Almanac section, we have a series of previous questions and queries from Yanmar GM owners along with answers. Many of these have been adapted from discussions on the “Yanmar Marine Engine Owner’s Group – Repair and Discussion” Facebook group which is a fantastic resource for getting help.

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