1974 Mercury 650 Thunderbolt

[drewf8]

Recently acquired '74 Crestliner that came with a '74 Mercury 650 3 cyl. model(Serial #3810908). Motor will start but is not consistent and struggles to stay running. Thinking I'm not getting good fuel flow and may replace the line from the tank as that has seen better days and see what happens. Anyone with any further insight into what could help. Grew up with boats but fairly new to working on boat motors.

Also if anyone know where I could find a manual online that would be great!

 

[Faztbullet]

Compression test first before $$$$ spent

 

[brodmann]

Any time I buy a used boat and motor, before I ever take it out on the water I either drain and replace gas, or pump some into a clear container and check for water. I then replace the water pump, spark plugs, foot grease and then test it in the driveway. If it doesn't run perfectly, I rebuild the carburetor. I know when buying a boat, you can't wait to get it on the water for the first time, but we all want the "first time" to be perfect and amazing, so I think a little patience an preparation is always worth the effort.

 

[racerone]

Those early 3 cylinder 650 models were not the best effort Mercury put on the market.----Compression test first.----Post your numbers.-----And you MUST install a new water pump impeller before you launch the boat.----Inspect the boat / transom too.---Aluminum boat or fiberglass ?

 

[drewf8]

Those early 3 cylinder 650 models were not the best effort Mercury put on the market.----Compression test first.----Post your numbers.-----And you MUST install a new water pump impeller before you launch the boat.----Inspect the boat / transom too.---Aluminum boat or fiberglass ?

Fiberglass. Hull and transom are actually in great shape so I’m not too concerned with that. Just want to get it in running condition and then I’ll work on cosmetics.

 

[drewf8]

Those early 3 cylinder 650 models were not the best effort Mercury put on the market.----Compression test first.----Post your numbers.-----And you MUST install a new water pump impeller before you launch the boat.----Inspect the boat / transom too.---Aluminum boat or fiberglass ?

I’ll do a compression test later this week once I have some free time and post what I get.