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2016 242 Engine surging

sapperfitz

Jet Boat Addict
Messages
48
Reaction score
75
Points
117
Location
Yelm, WA
Boat Make
Yamaha
Year
2016
Boat Model
242 Limited S E-Series
Boat Length
24
Hello,
I have a 2016 242 Limited S "E" with 25 hours on it. Two trips ago it developed a surging problem at idle and at around 4,000 RPM on the port engine. My top speed was also limited to 42 MPH. It seemed to me like something was stuck in my impeller, but I couldn't find anything there while I was out on the water. When I pulled the boat out of the water I found a small piece of wood wedged between the impeller and the vanes just aft. Problem solved (or so I thought). The next trip out I didn't have the idle surging, but did still have a surge at around 4,000 to 5,000 RPM but the engine would "jump" back to match the starboard engine (single lever on) at around 6,000. I suspected spark plugs but every plug looks brand new, no color at all, clean electrodes. I also pulled the jet pump and inspected the impeller and housing; everything still looks brand new except for a little surface rust on the impeller itself. Any ideas?
Thanks,
Fitz
 

Michael H

Active Member
Messages
3
Reaction score
1
Points
42
Boat Make
Yamaha
Year
2008
Boat Model
AR
Boat Length
21
Hello,
I have a 2016 242 Limited S "E" with 25 hours on it. Two trips ago it developed a surging problem at idle and at around 4,000 RPM on the port engine. My top speed was also limited to 42 MPH. It seemed to me like something was stuck in my impeller, but I couldn't find anything there while I was out on the water. When I pulled the boat out of the water I found a small piece of wood wedged between the impeller and the vanes just aft. Problem solved (or so I thought). The next trip out I didn't have the idle surging, but did still have a surge at around 4,000 to 5,000 RPM but the engine would "jump" back to match the starboard engine (single lever on) at around 6,000. I suspected spark plugs but every plug looks brand new, no color at all, clean electrodes. I also pulled the jet pump and inspected the impeller and housing; everything still looks brand new except for a little surface rust on the impeller itself. Any ideas?
Thanks,
Fitz
I have an AR210 and have a similar problem, left engine only, except at numerous rpm. The biggest jump for me is at ~7000 rpm, jumping to 8000 rpm, otherwise I get smaller jumps, like from 3500 to 4000. Top speed with bimini down and two on the boat is also about 42 rpm. A friend of mine told me that replacing spark plugs fixes most problems. Another told me if that doesn't work that it could be the injectors and that a mechanic can hook a computer up to it and tell which injector it is. I haven't tried either yet, since I don't want to take the boat out of service to be worked on. I might try the plugs this weekend though, since that's easy.
 

Matt Phillips

Jetboaters Captain
Messages
1,076
Reaction score
698
Points
217
Location
Lake Tahoe
Boat Make
Yamaha
Year
2017
Boat Model
242X E-Series
Boat Length
24
I'd start with the spark plugs...as replacing them seems to settle out a whole matter to quirks. Depending on how many hours you have on them and how long it's been, that's definitely the first place to look. When you change those plugs, remember only finger tight and then 1/4 turn after that...no more.
 

haknslash

Jetboaters Fleet Admiral
Messages
7,556
Reaction score
8,950
Points
547
Location
Lake Martin, AL
Boat Make
Moomba
Year
2019
Boat Model
Other
Boat Length
23
Be sure to check the gap of the plugs too.
 

Don R

Well-Known Member
Messages
11
Reaction score
16
Points
62
Location
Byron, IL
Boat Make
Yamaha
Year
2016
Boat Model
242 Limited S E-Series
Boat Length
24
Did you bring it in for your first service?
Possibly bad fuel?
 

sapperfitz

Jet Boat Addict
Messages
48
Reaction score
75
Points
117
Location
Yelm, WA
Boat Make
Yamaha
Year
2016
Boat Model
242 Limited S E-Series
Boat Length
24
Finally got the boat out again. I did change the plugs on just the port engine. problem solved. It seems strange though, the plugs I pulled out were all still gapped correctly and looked brand new. The boat only had 25 hours on it. How long are spark plugs lasting for everyone else?
 

cyclops

Jet Boat Addict
Messages
59
Reaction score
42
Points
97
Boat Make
Yamaha
Year
2015
Boat Model
Limited S
Boat Length
24
Finally got the boat out again. I did change the plugs on just the port engine. problem solved. It seems strange though, the plugs I pulled out were all still gapped correctly and looked brand new. The boat only had 25 hours on it. How long are spark plugs lasting for everyone else?
Did you ever have this problem again?
I suspect defective plug ?
 

sapperfitz

Jet Boat Addict
Messages
48
Reaction score
75
Points
117
Location
Yelm, WA
Boat Make
Yamaha
Year
2016
Boat Model
242 Limited S E-Series
Boat Length
24
Never had it again but I change the plugs every season.
 
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