Trouble w/ 2008 Yamaha 40HP 4 Stroke

[motorboating]

My husband and I recently purchased a used pontoon boat. The seller stated the engine ran well -- it only has 40 hours on the motor so we assumed it would be a safe purchase and we wouldn't have any engine troubles. Unfortunately, we were wrong. We took the boat out twice. First time, it took over 30 mins for the boat to crank and stay cranked. It wouldn't idle well, but once we got it out of the no wake zone and could turn it wide open it drove fine -- until we had to go in for the day and then we had the same problems with it cutting off while we were trying to keep it idle and load it.

My husband found a lose gas line when we got home and tightened that thinking that would resolve this issue. He took it out fishing Saturday morning and had the same issues, only worse... after it finally cranked and he put it in gear it tacked very high but was barely going. He decided not to risk getting stuck out on the lake and just brought it back in.

Any ideas on what could be the issue? We are hoping it may be something simple that we can repair ourselves.

Thanks!
Lisa

[boats.net]

If it hasn't been run in a while probably has fuel problems, may need to remove and clean carbs or vapor seperator tank and fuel pump.

[99yam40]

the F40 probably would not be a good motor for you to start learning about cleaning and adjusting the carbs on if not up on how and what to do, will need proper equipment also. So may be best to have a Yamaha shop do the work.

A Yamaha service manual is worth the money, it will tell you steps and equipment needed and then you can decide if you can do the different jobs over the years taking care of your motor.

The high RPMs in gear with out moving may be a spun hub in prop. It can be repaired at a prop shop or buy a new one of the same size and pitch. Always good to have a spare on board in case it is needed out on the water to make it back to port

[motorboating]

Thanks for the feedback, my husband said its fuel injected so it doesn't have carbs to clean? I did look into repair manuals and will be ordering one -- they seem really helpful.

Thanks again!
Lisa

[99yam40]

monitoring fuel pressures out and the vacuum pulled by fuel pump should show you if there are restrictions or problems with pumps and filters.

Like he said before inspect and clean the Vapor Separator Tank (VST)and screen/filter would be 1 thing to do to start out with. If you find nasty stuff in there then you may need to drain & clean fuel tank, flush lines, etc.

Injectors can be sent off to be tested and cleaned

Running a sick motor to see if it will get better is not the best thing for the motor if it is running lean.

[arny]

They have/had a campaign on the high pressure pump on the early serie injected 40hp- (3 cylinder). Was/is covered by Yamaha,ask a dealer about this.