Johnson 35 wot

"I have a 1984 johnson 35 hp o

"I have a 1984 johnson 35 hp on a jon boat I converted to a bass boat. when I completed this project, the boat ran good achieving about 27 mph. the next few times I took the boat out it ran progressively slower. It now runs about 10 mph and altough I don't have a tach I can hear it's not reaching wot. I have changed to smaller props, rebuilt the carb, gave it a tune up, but I am out of ideas how to remedy the problem. the motor run fine other than not aching wot. anybody have any ideas?"

"If you do not trailer the boa

"If you do not trailer the boat, I would suspect that the hull is fouled with marine life.

If you do trailer the boat and the hull is okay, check the compression (what are the readings?), and the spark.

Spark (with the spark plugs removed) should jump a 7/16" gap with a strong blue lightning like flame.... a real SNAP! Does it?

Note: the 7/16" gap is important. Do not simply attempt to check the spark by using the spark plugs which is a waste of time.

Plugs should be Champion QL77JC4 plugs, gapped at .040 .

Let us know what you find."

thanks for the rapid reponse.

thanks for the rapid reponse. first off the boat is trailered so marie growth is not problem. I have the proper champion plugs in and they were kind of a pain to find. you suggested testing the spark jump. would I do that by placing the plug 7/16" from a piece of properly gounded metal?

"Check that the carb opens ful

"Check that the carb opens full when throttle is at full.
Check that ignition plate is moving with throttle.
Hook the fuel hose from tank straight onto the carb, using the primer bulb as pump -does it help?"

"also the timing is advancing,

"also the timing is advancing, throttle is opening fully. linkages all good. I played with fuel/oil ratios running it richer and leaner but not to drasticly. the motor stsrts when cold very easy and sounds good when running. the only quirk the motor has is when it's hot and I give it too much throttle it falls on it's face(stalls) But it starts easily right back up. I am going to borrow a compression tester tommorrow afternoon so standby for those test results."

"the spark is good. I jumped a

"the spark is good. I jumped almost a full inch and had a definate pop. tommorrow I am going to run the boat with a buddy and a can of choke cleaner. he will drive so I can spray the choke cleaner to the carb. if it increases in rpms then it was starving for fuel, if it does nothing then it has all the fuel it needs. is my logic correct? I think that's what morton is trying to see. i'll still try his trick though. will keep you posted. thanks for your help,y'all. it's keeping me intrested in a project I was starting to get frustrated with."

Spray anything but 2% fuel mix

Spray anything but 2% fuel mix in the carb throat and You run the risk of seizing the engine.

"Bob,
I'm having the sa

"Bob,
I'm having the same trouble on some 40 year old smaller hp Evinrudes that I'm trying to restore for sentimental reasons. I've rebuilt/replaced every major component on them and still can't get them to rev much pass idle.
I have found that the coils and spark plug wires were bad, the fuel pump needed rebuilding, the carbs needed repair/rebuilding, and the bushing in the ignition plate(where the points cam rotates) was worn. I am enjoying tinkering with them but I haven't as yet been able to fix them.
Charles"

took the boat out today. I ran

took the boat out today. I ran the fuel line directly to the carb. it ran much better. I replaced the fuel lines and clamps. boat ran up to speed although I didn't bring my gps to see exacly how fast. there must have been a crack or block in a fuel line? but I now discovered another problem.

when I give the boat throtle it wants to stall. I can overcome this but feathering the throttle and eventually it it will go. I think I am running to rich or too lean. I don't see any adjustment screws on the carb. also I reacently moved from 4500 feet to about 500 feet elevation and I think the carb has it's original jets. how can I adjust this? do I use the red lever on the primer solinoid? the boat starts easier than ever and idles well.

"Seems You found the main &#39

"Seems You found the main 'problem'.
Before starting to adjust I would suggest a decarb of the engine with Engine Tuner/Sea Foam.
If Your carb has not been cleaned out in some years, do that first.(Dismantle and clean -no 'snake oil' in a can!)At least replace gasket #7.
Synchronize the engine according to the manual. Take special care about the pick-up point of the carb!
Adjust the idle mix screw so the engine runs at highest rpm at the lowest possible throttle setting, then back off the screw 1/4 turn.If still hesitating try to back off in steps of 1/8 turn. Screw #25.

"

where can I find the engine tu

where can I find the engine tune/de-carb?