The Johnno is having a bad day

[thelump]

Left Viccy point this morning at 330am. Very low tide and when in reverse hit bottom and thought nothing of it. Raised mator a tad. Continued on our merry way and when we got to the Platypus wreck at Peel she starts shuddering. Similar to running aground but was in 9m of water. Pulled it back to neutral and idled away fine. Go to take of and shuddering continues at around the 4000rpm mark. Pulled back throttle again and idles fine. Turn off and then restart. Away we go. No issues. Continue travel to just past the Myora then the same thing. Dont want this to happen over the bar so I turn back for home. Continues happening around the same time intervals. I was thinking powerpack maybe starting to pack it in again but then the curve ball. Overheat alarm comes on just near Coochie:-?.Plenty of water out of telltale:-? Idle back to ramp and head home with tail between legs. Any ideas folks?
Motor is 03 model 115 V4 Johnson 500hrs

[rosco1974]

maybe u sucked a bit of crap off the bottom into the leg when u hit bottom.not enough to totally block it but enough to still let some water up to the tell tail.i had the same thing happin on a 90hp merc i had once and thats what it was...i got up this morning to go but went back to sleep instead...need a lazy day b4 i go back to work after the holidays
cheers rosco

[finga]

Bung prop bush?? :)
Heat alarm may be another issue

[Chimo]

Did you happen to lift the lid and feel if the temp was the same on both sides?

I have two V4s similar to yours and found similar behavior when one side got hotter than the other. The motor protection operated and revs dropped and it did seem to run rough.

IMHO run the motor until it happens and then lift the lid and check head temps. You would feel the temp diff with your hand. If large difference the thermostat / cooling flow outside the thermostat may not be operating properly. This could be why all seems OK at lower revs when things are cooler. Maybe you sucked up some crud and its got caught? Anyhoo given the time it took me to fix mine I'd check temps first. And after that pull the thermo covers and check each one including the seat.

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[gazza2006au]

hitting things under the water is a pain in the ass around here its usually a stolen car sunk at the boat ramp ive hit one before so your problem would just be the clutch dog is slipping in the gearbox it could be your gear rod linkage (probably called something else) or at worse your drive shaft could be slipping inside of the crankshaft this will cause the over heating alarm to sound as the water pump isnt spinning full RPM as the engine is turning

[BM]

Perform a comp check and a spark check. Sounds like you may be dropping a cylinder at high rpm. What is your max rpm by the way? Are you reaching approx 5500rpm?

[littlemac]

hey jase,

Sorry to here that puts a bummer to the trip, but I think the problem is called I NEED AN UPGRADE haha

Cheers

brett

[thelump]

Perform a comp check and a spark check. Sounds like you may be dropping a cylinder at high rpm. What is your max rpm by the way? Are you reaching approx 5500rpm?

Thanks for the ideas but it seemed to rev to full revs just after I had turned it off and back on again. I can get 5800rpm trimmed right out. Once it starts to play up you cant get uch more than on the plane. Turn it off for like 15 seconds and re start and it goes like normal for a few minutes ??????????????????????

[thelump]

Did you happen to lift the lid and feel if the temp was the same on both sides?

I have two V4s similar to yours and found similar behavior when one side got hotter than the other. The motor protection operated and revs dropped and it did seem to run rough.

IMHO run the motor until it happens and then lift the lid and check head temps. You would feel the temp diff with your hand. If large difference the thermostat / cooling flow outside the thermostat may not be operating properly. This could be why all seems OK at lower revs when things are cooler. Maybe you sucked up some crud and its got caught? Anyhoo given the time it took me to fix mine I'd check temps first. And after that pull the thermo covers and check each one including the seat.

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Thanks Chimo. This makes sense although back at work tomorrow and time poor. I may put it in to get looked at and get a quote on a new 4 banger while its there.
Cheers Jason

[finga]

Does it rev right out when you cannot get on the plane or lack of revs the reason it won't get on the plane?

[thelump]

hey jase,

Sorry to here that puts a bummer to the trip, but I think the problem is called I NEED AN UPGRADE haha

Cheers

brett

Yes Brett I have sort of got her indoors thinking along those lines. Will do some pricing this week perhaps. Are you going to join up again next year?

[thelump]

Does it rev right out when you cannot get on the plane or lack of revs the reason it won't get on the plane?

Once it starts to splutter it will not rev past around 3000 without it starting to splutter but will happily idle and cruise along at around 2500. BUT if I shut it down for a few seconds then re start it it goes like normal for about 3-5 minutes before spluttering again. During this time it will reach full revs.

[Chimo]

"Once it starts to splutter it will not rev past around 3000 without it starting to splutter but will happily idle and cruise along at around 2500. BUT if I shut it down for a few seconds then re start it it goes like normal for about 3-5 minutes before spluttering again. During this time it will reach full revs."

This is exactly what mine did when it played up but it happened at 4500 plus after a little while and was worse on smooth flat water.

Lump; You know how I fixed it.

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[littlemac]

hey jase,

I will be signing up again and doing more trips,

cheers

brett

[gazza2006au]

now u have mentioned more about your problem it sounds electrical or fuel i reckon grab a cheap multimeter and the work shop manual and test all your electronics