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@help hard starting and low rpm 1.8 L motor

Ronnie

Jetboaters Fleet Admiral
Messages
8,775
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Location
SF Bay Area
Boat Make
Yamaha
Year
2010
Boat Model
Limited S
Boat Length
24
I’m camping with a lot of family this weekend and already on the water.
Last weekend both engines ran fine. Today after a week on the charger / maintainer I could not get the port engine would past 6000 rpm but the starboard engine still spins up to 7,600 rpm.
The port engine is also hard to start. And sometimes stalls and/or idles roughly soon after it starts. I’m not sure what it could be but I plan to do the following tomorrow first thing in the morning. 1. Check the oil. 2. Check the throttle cable. 3. Change the spark plugs. 4. Put duct tape around the intake part that used to hold the ribbon. I forgot the parts name, but it is hard black plastic and the factory ribbon/flame arrestor sits in it, Green hulk says that they sometimes delaminate and cause boost issues which result in low rpms, starting and idling problems. Green hulks solution is to sell a billet part with a new gasket . That won’t work for me this weekend so I’m going to go with duct/gorilla tape.

Anything else I should try?
 
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Sounds like a spark plug issue to me @Ronnie. Can the air intake part be easily removed? If not your duct tape fix would be faster than a plug change.
 
@Gym , thanks for replying. I recall that even under optimal conditions with the boat in the trailer it took time to complete the ribbon delete mod. So the concept is easy but the act is time consuming.

I am hoping that it is something simple and will be on the boat as soon as I see some sun light this morning.
 
@Gym , thanks for replying. I recall that even under optimal conditions with the boat in the trailer it took time to complete the ribbon delete mod. So the concept is easy but the act is time consuming.

I am hoping that it is something simple and will be on the boat as soon as I see some sun light this morning.
Ok, @Ronnie keep us posted.
 
Spark plugs would be my first thought, you are on the right path.
 
Also
I think you have to use [USERGROUP=9]@HELP[/USERGROUP] in the body not the subject line, i didn't get a notification on this
 
Green hulk says that they sometimes delaminate and cause boost issues which result in low rpms, starting and idling problems.
That applies primarily to boosted engines, SHO/SVHO. I doubt it is an issue here, but it could be a first.

I would consider fuel lines on the port side.

Hard starts are always port side, and I think it could be very simple - @SamCF posted on this somewhere. Basically, the main cue here is - it is always the port side engine. In the 1.8 twins, the port side fuel lines are very close to strbd engine exhaust manifold.

If you run the boat hard and then stop or slow down to low idle where cooling is crap (low water pressure) - that strbd exhaust cooks the fuel lines of the port engine - creating overheat or "vapor lock" conditions etc. (hot weather does not help either).

I find the blower ON when stopped helps and running in high idle helps to cool the engines before turning them off.


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Disconnect your batteries and reconnect tightly. I had a similar engine issue at Broken Bow one time and it was just loose battery connections. Might be an easy fix.
 
I would go with the spark plugs being the first suspect also. based on your description of hard start and low r p m's
 
How are you making out @Ronnie
 
It didn’t take long into the spark plug change this am to figure out what was wrong. See the pic, one of those things is no longer like the others.

The coil broke as did the top of the spark plug. For about an hour I tried tried to fish out, suck out and blow out the remaing pieces so I could install a new plug and a ghetto coil but I just could not do it with the materials and tools on hand. I debated running in one engine or not at all today but decided to run it the way it was. It ran rough, started hard and was sleek limited to 30 mph over a long build up time but it worked.

Had a great day on the water with family and friends, used all the tubes, ate throughout the day it was one of my best family camping days ever, just enjoying the company which I rarely see the other 363 days of the year. I must be getting old, good.
 

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So...What would cause the coil boot and top of the spark plug to break @Ronnie. Did you have the plugs out recently? Did you see any burn marks on the coil indicating a high tension leak which could cause the coil to degrade and break?
 
I don't think I have see the coil break like that. The symptoms were spark plugs so that was correct. I am glad it worked out for you and you had a great day with family.
 
I don’t know why the coil went bad the way it did but suspect that it got really hot/cooked since it feels crunchy, like I could squeeze it with both hands and turn it to dust, if that makes any sense.

I was out here just last weekend (I.e., camping weekend for my wife’s family) and the boat ran perfectly for three days straight. I got it home on Monday, plugged in the onboard charger and didn’t touch the boat again until Friday morning. It’s been a really hot week with temps exceeding 100 degrees but still only one of four coils failed. I hope the coils on the other engine still look good. I forgot to mention that I replaced the spark plugs just last Winter. All iridium in the boat and skis.

I hate to fix a problem before I know the cause (I.e., threat the symptom but not the cause) but in this case my plan is to, not right away, use a compressor to blow out the loose debris from the spark plug opening, use something to dig out the rest of the coil and hopefully use a spark plug wrench to remove what’s left of the spark plug. I will buy at least 2 maybe 3 new coils, 1 replacement and 2 spares. My brother meant well but I lol yesterday when he said “Maybe Napa Auto parts here in town (Waterford, CA) has one in stock”. Maybe they did since the coils looks like the same ones on my skis mr 1 engines which are also used in some Yamaha motor cycles but with the luck I was having I doubt it, besides I couldn’t deal with sourcing a part just then first as I had to remove what’s left of the old plug first and I couldn’t spend any more time than I had already. Even though I know I did what I could on a repair I still felt bad for not being able to pull it off (I need to turn in my McGyver card) but my guests would not have know a thing if some hadn’t seen me working on the boat early yesterday morning.

Today is the next and hopefully last adventure of this weekend, getting the boat and trailer home. I can’t call aaa until 1 when my new plan goes into effect. I’m going to need a low boy two truck to pick up my boat and trailer and deliver it to my home 100 miles away. If I get home before dark tonight I would be happy. I’ve attached a pic of why I need a tow for those that haven’t seen the related thread.

Anyway thanks for the responses on this matter.

H
 

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Hope y’all ( including the toys) made it home age and sound
 
Thanks, the summary story is aaa didn’t help, so I ended up trailering it home myself.

The longer version being I called aaa at 230, they said all good eta 45 mins. 30 mins later I get a call from the tow company saying not their area they will refer me. I called the referred company but the dispatcher didn’t know they don’t have a low boy trailer until almost an hour later. She referred me to an outside network provider who was supposed to give me a call with a quote (basically I pay $750 now and request reimbursement from aaa later). An hour later they called back and said not today, maybe tomorrow. At that point I did some checks on the rig including assuring proper tire inflation and grease on the three of the bearing buddies I had left (all three had plenty of grease in them) then I hit the slow lane home for a hundred miles. Safe, sound and wiser I think.

A pic of the Ray Rig, a thing of beauty in my eyes.

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Thanks, the summary story is aaa didn’t help, so I ended up trailering it home myself.

The longer version being I called aaa at 230, they said all good eta 45 mins. 30 mins later I get a call from the tow company saying not their area they will refer me. I called the referred company but the dispatcher didn’t know they don’t have a low boy trailer until almost an hour later. She referred me to an outside network provider who was supposed to give me a call with a quote (basically I pay $750 now and request reimbursement from aaa later). An hour later they called back and said not today, maybe tomorrow. At that point I did some checks on the rig including assuring proper tire inflation and grease on the three of the bearing buddies I had left (all three had plenty of grease in them) then I hit the slow lane home for a hundred miles. Safe, sound and wiser I think.

A pic of the Ray Rig, a thing of beauty in my eyes.

View attachment 103263
Thanks for posting, scary $hit but I would do the same (...and pray hard, lol).

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Quick update, I ordered an oem ignition coil from amazon today, $125 shipped, eta end of August.
I also broke out the compressor to blow the remaining parts of the top of the spark plug and coil out.
 
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