• Welcome to Jetboaters.net!

    We are delighted you have found your way to the best Jet Boaters Forum on the internet! Please consider Signing Up so that you can enjoy all the features and offers on the forum. We have members with boats from all the major manufacturers including Yamaha, Seadoo, Scarab and Chaparral. We don't email you SPAM, and the site is totally non-commercial. So what's to lose? IT IS FREE!

    Membership allows you to ask questions (no matter how mundane), meet up with other jet boaters, see full images (not just thumbnails), browse the member map and qualifies you for members only discounts offered by vendors who run specials for our members only! (It also gets rid of this banner!)

    free hit counter

Hard to start

Jason spanick

Active Member
Messages
17
Reaction score
4
Points
32
Boat Make
Yamaha
Year
2018
Boat Model
Limited S
Boat Length
21
Ok guys. I need someone to explain this to me. After spending a few hours in float mode One of my engines on my 2018 212 limited s was hard to start. It took five attempts to start. After it started it missed until I gave it throttle after that no problems. This happened a few weeks ago and it was both engines, on separate occasions. Can someone explain this to me.
 

212s

Jetboaters Captain
Messages
2,261
Reaction score
1,598
Points
237
Location
1000 Islands
Boat Make
Yamaha
Year
2020
Boat Model
212S
Boat Length
21
Ok guys. I need someone to explain this to me. After spending a few hours in float mode One of my engines on my 2018 212 limited s was hard to start. It took five attempts to start. After it started it missed until I gave it throttle after that no problems. This happened a few weeks ago and it was both engines, on separate occasions. Can someone explain this to me.
Found a similar issue on ours but I believe it turns out to be heat related that was mentioned in another thread. I was shutting down the engines after running them at cruising speed and not letting the system cool down a bit first. Now that I idle for a couple minutes first to cool them down, haven't really had the issue.

Might not be your issue though as mine don't miss at all, just hard to start when shut down hot. Missing would indicate the plugs may be fouling a bit as the engine fuel mixture is quite rich at idle and the plugs could be worn or the spark gap is too large causing a poor spark. I've read here that these engines are sensitive to spark plug gap, too small and the spark is not big enough for a clean burn. Too large and the spark is too weak to get a clean burn.
 

Jason spanick

Active Member
Messages
17
Reaction score
4
Points
32
Boat Make
Yamaha
Year
2018
Boat Model
Limited S
Boat Length
21
Found a similar issue on ours but I believe it turns out to be heat related that was mentioned in another thread. I was shutting down the engines after running them at cruising speed and not letting the system cool down a bit first. Now that I idle for a couple minutes first to cool them down, haven't really had the issue.

Might not be your issue though as mine don't miss at all, just hard to start when shut down hot. Missing would indicate the plugs may be fouling a bit as the engine fuel mixture is quite rich at idle and the plugs could be worn or the spark gap is too large causing a poor spark. I've read here that these engines are sensitive to spark plug gap, too small and the spark is not big enough for a clean burn. Too large and the spark is too weak to get a clean burn.
The first time it happened I checked the plugs and gaps everything was in spec. It honestly seemed like a fuel issue
 

212s

Jetboaters Captain
Messages
2,261
Reaction score
1,598
Points
237
Location
1000 Islands
Boat Make
Yamaha
Year
2020
Boat Model
212S
Boat Length
21
The first time it happened I checked the plugs and gaps everything was in spec. It honestly seemed like a fuel issue
Might just be heat causing some vapour lock. Since cooling the engines down longer after running (they stay quite warm in the engine compartment), haven't had the issue again. Today was a hot one 88 in the shade, and no issues with several stops and starts.
 

MrBubbaGump

Jet Boat Junkie
Messages
403
Reaction score
416
Points
137
Boat Make
Yamaha
Year
2022
Boat Model
FSH Sport
Boat Length
21
Ok so searching this tread this issue seems to come up fairly often... For the second time going out had this problem with my starboard engine not wanting to start after sitting out on the water for 5+ hours. I don't crank for more than 3-5 seconds at a time but tried at least 10 times today maybe more (with breaks in between) and she would not start! It would act like it wanted too like idle rough for a quick 2 or 3 seconds and die. Eventually it started and ran with no problems. Got back to the dock brought home and started up again when cleaning. I will say the port engine fires every time the second you turn the key. While the starboard does a quick 1,2 crank almost every time but never thought anything of it till just now... Didn't find it abnormal really.
 

Cobra Jet Steering LLC

Jetboaters Admiral
Vendor
Messages
5,910
Reaction score
5,380
Points
452
Location
Florida
Boat Make
Yamaha
Year
2021
Boat Model
Other
Boat Length
Other
that was 3 years ago hopefully he figured it out LOL
 

MrBubbaGump

Jet Boat Junkie
Messages
403
Reaction score
416
Points
137
Boat Make
Yamaha
Year
2022
Boat Model
FSH Sport
Boat Length
21
that was 3 years ago hopefully he figured it out LOL
I hope so... Because that's the issue I am having now! wasn't trying to start a new thread on something that has already come up.
 

Cobra Jet Steering LLC

Jetboaters Admiral
Vendor
Messages
5,910
Reaction score
5,380
Points
452
Location
Florida
Boat Make
Yamaha
Year
2021
Boat Model
Other
Boat Length
Other
I hope so... Because that's the issue I am having now! wasn't trying to start a new thread on something that has already come up.
check your neutral switch if it cranks but won't start move the throttle back and forth a couple times some of the switches will give you a problem I had one myself.
 

lazergeek

Jetboaters Lieutenant
Messages
645
Reaction score
652
Points
167
Location
South Florida
Boat Make
Yamaha
Year
2021
Boat Model
FSH Sport
Boat Length
21
I hope so... Because that's the issue I am having now! wasn't trying to start a new thread on something that has already come up.
I had that issue in January on my starboard engine, I repalced my plugs which were ony 6 months old and has not happened again since.
 

FSH 210 Sport

Jetboaters Admiral
Messages
6,391
Reaction score
7,554
Points
447
Location
Tranquility Base
Boat Make
Yamaha
Year
2020
Boat Model
FSH Sport
Boat Length
21
There are a couple of things you can do to try and keep this from happening. If you have been cruising for a while before shutting the engines off, as you arrive at your destination allow the engines to idle for a while to allow them to cool down, I run the pilot water through my fingers when I get where I’m going to feel how warm that water is, it’s coming from the oil coolers. At the same time turn the bilge blowers on to keep the heat from building in the engine bay. I’ll let the engines idle maybe 5 mins until the pilot water output turns cooler, that’s a lot of heat that’s been pulled out of the engine via the oil. I have not had a problem with start up after a long cruise or “sport boating” around as long as I do that.

As @lazergeek found though a fresh set of plugs can set things right as well.
 

MrBubbaGump

Jet Boat Junkie
Messages
403
Reaction score
416
Points
137
Boat Make
Yamaha
Year
2022
Boat Model
FSH Sport
Boat Length
21
By no means am I a spark plug expert but I decided that's the easiest thing I can try before taking it to sit at the dealer all summer. Below are what the old plugs looked like, I don't really see anything too wrong with them. Though the starboard (bottom set) do look slightly worse than the port side.
IMG_2790.jpgIMG_2791.jpg
 

lazergeek

Jetboaters Lieutenant
Messages
645
Reaction score
652
Points
167
Location
South Florida
Boat Make
Yamaha
Year
2021
Boat Model
FSH Sport
Boat Length
21
My Starboard plugs always look worse then my port engine plugs.
 

FSH 210 Sport

Jetboaters Admiral
Messages
6,391
Reaction score
7,554
Points
447
Location
Tranquility Base
Boat Make
Yamaha
Year
2020
Boat Model
FSH Sport
Boat Length
21
My Starboard plugs always look worse then my port engine plugs.
That’s interesting… my starboard engine run noticeably rougher than the port and two of the three plugs have a small about of build up on the inner steel part of the plug down at the end.. was going to try some new coil packs. Or try moving them over to the port engine to see if the rough running follows them.
 

MrBubbaGump

Jet Boat Junkie
Messages
403
Reaction score
416
Points
137
Boat Make
Yamaha
Year
2022
Boat Model
FSH Sport
Boat Length
21
That’s interesting… my starboard engine run noticeably rougher than the port and two of the three plugs have a small about of build up on the inner steel part of the plug down at the end.. was going to try some new coil packs. Or try moving them over to the port engine to see if the rough running follows them.
I agree the starboard runs rougher on mine as well.
 

FSH 210 Sport

Jetboaters Admiral
Messages
6,391
Reaction score
7,554
Points
447
Location
Tranquility Base
Boat Make
Yamaha
Year
2020
Boat Model
FSH Sport
Boat Length
21
By no means am I a spark plug expert but I decided that's the easiest thing I can try before taking it to sit at the dealer all summer. Below are what the old plugs looked like, I don't really see anything too wrong with them. Though the starboard (bottom set) do look slightly worse than the port side.
View attachment 202740View attachment 202741
Those plugs look pretty good… I can see a couple threads of heat which is good. However, there appears to be some decent electrode wear on a few of them.

how many hours on them? What is the current gap and what was the installed gap?

I‘d use a little less thread lube on those plugs, just a little less, and make sure you get the lube all the way down into the threads when putting it on. I brush on the old school copper anti seize then push it into the threads with a gloved finger, the use a paper towel to wipe off the excess.

Is that the wacker paste JBP sells?
 
Last edited:

FSH 210 Sport

Jetboaters Admiral
Messages
6,391
Reaction score
7,554
Points
447
Location
Tranquility Base
Boat Make
Yamaha
Year
2020
Boat Model
FSH Sport
Boat Length
21
I agree the starboard runs rougher on mine as well.
Huh, what a trip.

I’ve also got a slight, very slight, oscillation at idle going on one of the engines even after new plugs.

Your plugs gap should be .028” to start out with, the limit is .031”. When I pulled my last set out, the gap had grown to roughly .035-.038”.
 

MrBubbaGump

Jet Boat Junkie
Messages
403
Reaction score
416
Points
137
Boat Make
Yamaha
Year
2022
Boat Model
FSH Sport
Boat Length
21
Dealer did them about 15 hours ago... Starboard side wasn't exact when I pulled them out between 30-31ish. Port side all seemed to be right at 29-30. I tried to put them right at 28-29ish. Did not put any anti seize this time... I was reading the great debate on that. I probably will go back and put some on though always have not sure if I agree with not using it. I know the manual says to put some on.
 

FSH 210 Sport

Jetboaters Admiral
Messages
6,391
Reaction score
7,554
Points
447
Location
Tranquility Base
Boat Make
Yamaha
Year
2020
Boat Model
FSH Sport
Boat Length
21
Ask @lazergeek how it worked out when the dealer didn’t put anti seize on is plugs… I use a torque wrench on mine when I install them with just a little bit of antiseize on the threads… and I’m in fresh water! If the manual says to then there is probably some good experience there that they had..
 

FSH 210 Sport

Jetboaters Admiral
Messages
6,391
Reaction score
7,554
Points
447
Location
Tranquility Base
Boat Make
Yamaha
Year
2020
Boat Model
FSH Sport
Boat Length
21
See how the electrode is not square any more? Its at an angle. A couple of your other plugs have a nice square electrodes which is good…

I took a closer look at your starboard plugs and they look almost identical to mine in that two cylinders next to each other don’t seem to burn as clean… 🤔

77373464-4397-40A7-B49F-743EAC78BAC0.jpeg
 

lazergeek

Jetboaters Lieutenant
Messages
645
Reaction score
652
Points
167
Location
South Florida
Boat Make
Yamaha
Year
2021
Boat Model
FSH Sport
Boat Length
21
Ask @lazergeek how it worked out when the dealer didn’t put anti seize on is plugs… I use a torque wrench on mine when I install them with just a little bit of antiseize on the threads… and I’m in fresh water! If the manual says to then there is probably some good experience there that they had..
It wasnt even the deaer, It was the Factory installed plugs. They did not change my plugs on my 10 hours service. My dealer said they always use Anti Seize and $1200 later I agree its worrht the piece if mind.
 
Top