2000 70hp Johnson

[whofan]

I have this motor on a 16ft lund fisherman. My boat is rated for maxinum horse power of 90. Would I regret trading this motor for a 90 or 90 four stroke or even a 70 four stroke? The 70 Johnson has a reputation as being a great motor. Over all I like it but its very touchy as far carburator adjustment. After trolling for a while it bogs out and quits. Im not in a position to trade off now but anybody have a opinion on this set up? I bought the motor new in 01. Should I just keep it and run it til its tired?

 

[DJ]

Re: 2000 70hp Johnson

oderboat,<br /><br />The 90 will turn your boat into a rocket. That's not always a bad thing. <br /><br />Have you thought about a kicker?<br /><br />The fourstroke will be considerably heavier.

 

[OBJ]

Re: 2000 70hp Johnson

DJ is right, a 90hp will turn it into a rocket. I run an 85 16' StarCraft Supersport, open bow. I use to run a 50hp on it...well the lid said 50 anyhow. Then I run across a 90hp (86) that had my name all over it. So.....I switched engines after reworking the 90. It scares me. That is the truth. The boat is very stable and is rated for 90 but with all that extra get up and go, I'm always centered on driving and seldom go WOT.

 

[ob]

Re: 2000 70hp Johnson

oberboat,The stalling symptom of your engine is likely due to the idle mix being out of adjustment and or the carb link roller being out of adjustment.With the controls in the neutral position ,insure that the carb link roller is on center with the scribe line of the fiber throttle cam and "just touching".There is an adjustment screw that can be loosened and retightened to make this adjustment.I believe the carbs on your engine will have an idle mix screw on each .They are located on the starboard side of the carbs.These should be opened(counterclockwise)2 1/2 to 3 turns.You can dtermine the exact position of each by turning them closed(clockwise)in 1/2 turn incriments ,and counting the turns it takes to gently seat them.Once this is done ,simply open them up 2 1/2 turns initially and water test boat.A final adjustment in the water may be necessary,but once you know where they're at it's easy.Hope this has been of some help.<br /><br />PS,that engine should be propped to turn between 5500-6000 rpms at wide open throttle.Nearer 6000 is better.Any less is lugging the engine at any throttle setting.

 

[whofan]

Re: 2000 70hp Johnson

Yes I have thought about maybe a 8hp kicker. My boat originaly had a 50 Johnson both the boat and motor were 99 models, so I already traded up to the 70 wish I went with the 90 at times.

 

[whofan]

Re: 2000 70hp Johnson

ob thanks for your reply! The motor will turn 5500 RPM at WOT. I think it has a 17 inch prop on it. stock for the motor. I will try adjusting it myself. always had my dealer do it before. This motor has run and will run like a top at times its just inconsistant. Moody I guess LOL!

 

[ob]

Re: 2000 70hp Johnson

Yep.Good motors.I've run several 2 and 3 cylinder loopers over the years.Look at those adjustments closely as they will drastically effect the slow speed and throttle up performance of that engine.I had the same dying out issue with my most recent 70 as well until I made the necessary adjustments.Many others with the same engine have had the same complaints.

 

[ob]

Re: 2000 70hp Johnson

oberboat,Did you ever get your stalling issue straightened out?

 

[whofan]

Re: 2000 70hp Johnson

Not yet its still in winter storage. I will be getting it out in a few weeks though. Michigans U.P isnt too kind to us boaters. I will definently be checking into it after I burn the fogging oil off. The motor always has liked to be run close to wide open. my dealer has ajusted it a few times it always ran great right after leaving the shop. My first time out last summer I was totally floored by how good it ran after sitting all winter. I couldnt believe it.Just at times it bogs at idle and somtimes I have to feather acceleration or it will stall.After a while trolling it will quit as if out of fuel. Ill try to keep you posted. Thanks a million ob!!!!! <br /><br /> I did ask the mechanic if I should locktite the adjustment screws LOL!