35 hp johnson wot pronlems

[huntingtheworld]

1979 35 hp will not go wot.carb is clean and both cylinders are getting fire.all electronics are new.It runs like 6.6 mph wot.prop is good.i switched props.normal top speed is like 30.Any help?It is not getting too much fuel or running lean.motor is running perfect just not running high rpm.its like im pulling another boat.any help?

 

[F_R]

Re: 35 hp johnson wot pronlems

Looks like you have been concentrating on the electronics etc., but nevertheless it most likely it is running on one cylinder. Have you checked the compression to make sure you aren't beating a dead horse?

OK, assuming it has good and equal compression, are you sure it isn't getting water in one cylinder?

My advice is to remove and ground one spark plug wire and see how it runs. Then do the same with the other wire. Chances are it won't make any difference with one grounded, but won't run at all with the other one grounded. That is the good one. Now zero in on the other one to see why it isn't firing. Could be as simple as a spark plug or as bad as a blown piston (which of course you would have found with the compression test).

The carburetor is the LEAST likely to be the problem.

 

[huntingtheworld]

Re: 35 hp johnson wot pronlems

yesterday i was on the water and i checked spark with a screwdriver and had spark on both cylinders.

Looks like you have been concentrating on the electronics etc., but nevertheless it most likely it is running on one cylinder. Have you checked the compression to make sure you aren't beating a dead horse?

OK, assuming it has good and equal compression, are you sure it isn't getting water in one cylinder?

My advice is to remove and ground one spark plug wire and see how it runs. Then do the same with the other wire. Chances are it won't make any difference with one grounded, but won't run at all with the other one grounded. That is the good one. Now zero in on the other one to see why it isn't firing. Could be as simple as a spark plug or as bad as a blown piston (which of course you would have found with the compression test).

The carburetor is the LEAST likely to be the problem.

 

[F_R]

Re: 35 hp johnson wot pronlems

But was it actually RUNNING on both cylinders???

 

[Tim Frank]

Re: 35 hp johnson wot pronlems

yesterday i was on the water and i checked spark with a screwdriver and had spark on both cylinders.

A screwdriver is probably better than using a toothbrush, but not much.
If you get around to doing the tests that FR suggested and report back, we may be able to help.

 

[huntingtheworld]

Re: 35 hp johnson wot pronlems

Im about to pull the fly wheel.It used to rattle real bad under the fly wheel,im about to check that real quick.

A screwdriver is probably better than using a toothbrush, but not much.
If you get around to doing the tests that FR suggested and report back, we may be able to help.

 

[likitvi]

Re: 35 hp johnson wot pronlems

I would do the 2 quick and simple tests very first, that is check that choke butterfly is open and that throttle butterfly is wide open at WOT. After that the ignition test suggested already. On my 1980 35hp the collar on throttle control rod had just turned loose and it caused the exact symptoms you describe.

 

[huntingtheworld]

Re: 35 hp johnson wot pronlems

ok i did the compression check both cylinders were around 120,very close.im doing the spark next.

 

[huntingtheworld]

Re: 35 hp johnson wot pronlems

butterfly is not stuck i tried that on the water.when the motor is wot so is the carbs,I checked that when it broke on the water.

 

[huntingtheworld]

Re: 35 hp johnson wot pronlems

ok so i checked to see if both cylinders and working and they are??? i pulled the wire on one and cranked it and it ran.and i did the same to the other.how is this possible lol ive done went over everything possible.How many times should i turn the screw on the carb for it to be close to stock?

 

[F_R]

Re: 35 hp johnson wot pronlems

The mixture needle has virtually no effect on high speed operation. It is an idle mixture adjustment. Set it where it idles the best.So, you are telling us that it runs on both cylinders and all the linkages are correct. Right?

There is something going on here that you are not telling us.

Don't laugh at this next suggestion---I've seen it a lot of times. Is the boat full of water? You wouldn't believe how many times I've drained 50 gallons of water out of a boat that wouldn't perform. It was trapped between the floor and hull. 50 gallons equates to 400 pounds.

How about marine growth on the bottom? It is amazing how much effect just a few barnacles will have.

If you were to bring this rig to me at my old dealership job, I'd put a test prop on the motor and see if it is developing it's rated horsepower/RPM. At least I'd then know if there actually is something wrong with the motor.

 

[Tim Frank]

Re: 35 hp johnson wot pronlems

Do you have a tach on the boat?

 

[huntingtheworld]

Re: 35 hp johnson wot pronlems

no extra water or nothing on the bottom.the boat is like new.Its a v bottom boat with 2 batterys 3 people and full on gas.I have pulled the lower unit off but im pretty sure the linkage is right.Thats about it.I honestly dont know what else to do.I was told sometimes a seal under the fly wheel around the shaft can go bad and mayby cause this?

Do you have a tach on the boat?

 

[likitvi]

Re: 35 hp johnson wot pronlems

Ok, so you changed prop. What kind of a boat is that more precisely, length, weight? Are you certain that the top speed was 30mph, it should mean that the engine is certainly has enough power for the boat.

How does the engine operate when trying to go WOT? Not at its expected maximum rpm, reaches maximum rpm but low top speed, or how?

Was the previous propeller the same diameter, pitch, and material? When trying to reach proper top speed, can you try to move all moveable weight forward and see if that helps? And perhaps try also the old propeller for troubleshooting. It is possible the propeller has too much pitch to get the boat on plane.

 

[F_R]

Re: 35 hp johnson wot pronlems

no extra water or nothing on the bottom.the boat is like new.Its a v bottom boat with 2 batterys 3 people and full on gas.I have pulled the lower unit off but im pretty sure the linkage is right.Thats about it.I honestly dont know what else to do.I was told sometimes a seal under the fly wheel around the shaft can go bad and mayby cause this?

Now you are making desperate attempts. The crankshaft seal might cause a lousy idle if shot, but not a WOT problem. The old motors with breaker points would foul the points from a leaking seal, but your motor does not have points. And I don't know what you expected to find in the lower unit, but it didn't help did it?

Did the problem start when you changed the prop? That COULD be the cause---maybe.

Well, we could guess all day. I say you need to take it to a qualified shop with certified Johnson technicians, hopefully with a correct test prop. Or keep on guessing.

 

[Tim Frank]

Re: 35 hp johnson wot pronlems

Quote Originally Posted by Tim Frank View Post
Do you have a tach on the boat?

no extra water or nothing on the bottom.the boat is like new.Its a v bottom boat with 2 batterys 3 people and full on gas.I have pulled the lower unit off but im pretty sure the linkage is right.Thats about it.I honestly dont know what else to do.I was told sometimes a seal under the fly wheel around the shaft can go bad and mayby cause this?

One of the problems here is that you do not seem to be approaching this systematically, and don't seem to be paying a lot of attention to suggestions and questions .
i.e. you included my question about whether you have a tach in your last response, but did not answer.; we still have no idea whether you have one or not.

Trying to help from a distance, without much info is a mug's game.

How long have you had the boat/motor?
When was the last time that it ran at 30 MPH

with 2 batterys 3 people and full on gas

??
Or did you buy it after test driving it with just you in the boat?

If this is the first use this season, verify the quality of your gas/absence of water in the tank. I've seen this condition caused far more often by 1" of water in the tank than a lower unit issue.

Check the simple things first.

 

[huntingtheworld]

Re: 35 hp johnson wot pronlems

NO TACh,Ive had the boat 2 years.It ran 30 last time i took it out last summer.And their is no water in the tank or bad gas.

One of the problems here is that you do not seem to be approaching this systematically, and don't seem to be paying a lot of attention to suggestions and questions .
i.e. you included my question about whether you have a tach in your last response, but did not answer.; we still have no idea whether you have one or not.

Trying to help from a distance, without much info is a mug's game.

How long have you had the boat/motor?
When was the last time that it ran at 30 MPH ??
Or did you buy it after test driving it with just you in the boat?

If this is the first use this season, verify the quality of your gas/absence of water in the tank. I've seen this condition caused far more often by 1" of water in the tank than a lower unit issue.

Check the simple things first.

 

[huntingtheworld]

Re: 35 hp johnson wot pronlems

and i have 2 props for the boat.The one that came with it and a different pitched prop.Both do the same.The prop is fine.

 

[huntingtheworld]

Re: 35 hp johnson wot pronlems

all weight was moved forward and still nothing.It went slower.I think its the throttle advanced.I may of missed something idk.ill take it out this week and find out.

 

[huntingtheworld]

Re: 35 hp johnson wot pronlems

boat is a 14 foot triden fish and ski.not too sure on weight.