1998 johnson venom questions 200hp

[mkgarrison5]

first off i love the board and lots of good info.. here are my questions

1. when it first starts (and yes i know it take a lil time to get it cranked) it smokes like the dickens. i mean hazes the marina. after warm up its not that bad. could this be piston ring issues

2. we had the VRO replaced last year but i still get a hesitation (shakes the boat) when going around 25-46 mph on the water at a steady throttle. the plugs were installed less than 50 hours of run time.

3. bad idling.. well from what i can tell. its my first boat and had it for 4 years and the idling can be rough. shakes the whole back end of the boat and you can see the motor flopping around in the back. granted its worse when cold but when its warm it still does it to a degree..

are these just the nature of the beast or is there someting i could do to help this??

btw its never been de carboned. just add a fuel stablilizer to winterize and change the LU gear oil. thats it.. any help. sorry for the noob questions but i need it lol

thanks guys

[mkgarrison5]

anyone have any idea on this??

-- since its never been decarbed in the 9 years of existance, should i NOT decarb it?? the tech i talked to said if there is a ring that is broken and held in place by carbon build up then de carbing would ruin it.. any truth on this matter??

[ChampioNman]

Have a compression test done and also check the condition of the recirc valves and their hoses. They are on the intake manifold 3 per side.

[mkgarrison5]

i dont know that much about boat motors unfortunetlly.. could my local shop do this without ripping me a new one?? LOL..... as far as decarbing, should i still do it though its NEVER been done in 8 years?

[PJCodner]

I would get a compression test done first then if that all checks out ok then do the decarb. If there is a broken ring you will more than likely see that in the compression check. Plus if the ring is broken it will fail sooner or later and it would in my opinion be better to break during decarb then 5 miles from the landing running wide open.

Also if you don't know much about the motor then I would either get used to paying a mechanic to check things or get yourself a service manual so that you can do some things yourself. I didn't know what the recirc valves were either so I got a manual and there they are. Even tells you how to check them.

[mkgarrison5]

i have the book on it.. i tinker with jeeps and etc so i am not totally dumbfounded around motors but i do have the complete repair book for johnsons for that year.. how much does a compresion test run?

[PJCodner]

You can do that yourself if you have a guage. I think guages are anywhere from $20 and up.

[mkgarrison5]

hmm one thing was brought up by a guy i know and he said since i installed the plugs myself and didnt gap them nor indexed them?? i just went to the dealer and bought plugs assuming they were gapped... stupid me... i dont know how to index them or whatever that term is... this gauge can be used to do a compression test??

[Bassmeister]

98 Johnson Venom is a carb engine, plugs do not have to be indexed.

[mkgarrison5]

hmm i thought it was fuel injected along with oil injected?? goes to show what i know


-- as for the skipping when cruising the lake between 25 and 40 mph what can cause that? carbon build up?? bad gas?? he uses 89 octane fuel in it and has stabilizing additive (stabil) in the tank.....

i appreciate the help guys!!

the vro was replaced last year along with plugs.