1986 twin 50 hp popping out of gear

[cofused 50hp]

hey guys I have twin 50 evenrudes, my problem is this; motors run great no problem with idle or cooling however when i try to get my speed up my motors seem to slip into netrual and over rev. When i drop down the speed lever the rev lowers and it slips back into gear. I am not sure if it is a throttle linkage issue or a lower leg issue. My likage does however seem too forward than what I am used to. Could it be that my throttle linkage is missing somthing and that when i push the speed it has a safety system for too high rev. It only happens when I reach about 15mph. when veiwing the wash from the motors it seems to expose the props could it also be that may need to put some dolphins on

 

[JB]

Re: 1986 twin 50 hp popping out of gear

Howdy, Cofused.<br /><br />Welcome to the board.<br /><br />It seems possible that your engines are popping out of gear, but unlikely that they would pop back in gear when you take the torque load off of them. One, maybe, but I don't think two.<br /><br />I think what is happening is that you are ventilating your props; they are getting air and making foam. They have no bite in the foam and spin.<br /><br />The most common causes of prop ventilation are: <br /><br />1. Incorrect rigging of the engine(s) so that the anti-ventilation (so-called "cavitation") plate(s) are above the level of the bottom of the boat.<br /><br />2. Incorrect trimming of the engines so that the props are not adequately submerged.<br /><br />3. Use of short (15") shaft engines on a 20" transom or long (20") shaft engines on a 25" transom.<br /><br />If the engines do not CLUNK!! when they change rpm ventilation is your culprit. If they do CLUNK!! you may need to adjust your shifting linkage.<br /><br />Good luck, and let us know what you find.

 

[Duck Loads]

Re: 1986 twin 50 hp popping out of gear

Several years ago, I had a 25hp Johnson that would pop out of gear with a BIG BANG. The first time it happened, I just knew I hit a big log. I had to get new gears and shifter dog.<br /><br />Be safe,<br />Duck L.

 

[cofused 50hp]

Re: 1986 twin 50 hp popping out of gear

thanks guys I do think it is the ventalation because for two motors to react the same time at around the same speed it must be the shafts are to short for the transsom. however is there a cheaper way to correct this issue rather than placing an extended leg. Right know it sits on and extended homemade transom and it is currently tilted at the second to the last bottom hole. would lowering the tilt to last hole or going higher would fix the problem or is it possible to place dolphins to hold the water in place

 

[JB]

Re: 1986 twin 50 hp popping out of gear

Aloha, Philip.<br /><br />Please tell us more about your boat, the transom and the engines.<br /><br />Then we will be better able to give you good advice.

 

[cofused 50hp]

Re: 1986 twin 50 hp popping out of gear

Okay here i go my boat is 20 feet without the transom. the extension transom extends out about 2 feet made out of heavy metal. 8 FEET BEARCH engines are about 14in apart the bottom leg lines up right at the bottom of the boat. The boat is an old rennelle that sits very high of the water I say about 3' 1/2". I was going to cut the transom a little so the engines sat lower but I am not sure how lower i could go. right now the back wash from the boat goes right up in the motors so I am afraid if I go lower the back wash would be to much. Trolling speed is perfect I can go without over rev about 12mph but if i go faster the boat planes forcing my motors out of the water. I honestly thought this was the problem but a friend of mine says his motor was doing the same thing and it was due to his linkage. What he described was exactly happening. my throttle is being pushed to far foward and no matter how much i adjust it dosen't do anything. He talked about some plastic bushingings on the throttle of the engine. He explained when the throttle goes up to much it pops out of gear. I just do not have the money to spend on new motors or a longer leg. I have faith in these motors it takes me off the waianae coast for about 120 miles a trip with no problems. THANK YOU i DO APPRECIATE THE HELP AND SUGGESTIONS THAT WILL HELP ME RESOLVE THIS ISSUE. i HAVE THOUGHT OF CONVERTING TO A FIBER GLASS TRANSOM THAT A GUY IN THE BIGISLAND IS WILLING TO CUTOMIZE FOR ABOUT 4OO.OO BUT AGAIN i WANT TO TRY TO BE AS CONSERVITIVE AS POSSIBLE.

 

[OBJ]

Re: 1986 twin 50 hp popping out of gear

Hi Phillip....<br /><br />In your descripton, you said the "bottom legs lines up with the bottom of the boat". Does this mean the gear case of each motor is above the keel of the boat?<br /><br />And is the transom extension a factory made extension or an add-on?

 

[cofused 50hp]

Re: 1986 twin 50 hp popping out of gear

my transom is an add on it is conter weghted with a cutom made 130 gallon fuel tank that sits foward in the bow. the top of the lower leg sits just above the bottom of the boat about 3" to be exact so by closer examination ventalation could be the issue i am experincing

 

[bob58]

Re: 1986 twin 50 hp popping out of gear

with your custom extension placing the motors 2ft back from the transom, you might be able to trim the motors up a notch or two, allowing the stern to sit lower in the water as you transition to a plane keeping the legs lower in the water also. <br />Might just luck out there, it is worth a try!

 

[cvx35]

Re: 1986 twin 50 hp popping out of gear

I can't believe you spent all that money cusomizing your transom without having, a mechanic test the boat in a lake to see what the deal is.......it could be anything.....from the height or possibly shifter and gear lock ware.......oh well, i know it's 2 motors but in the future if it is shifter and gearlock ware, you need to shift it on into gear.....do not ease it in...hope ya figure it out.......please see someone who can tell what's goin' on by testing it in the water...good luck buddy

 

[rickdb1boat]

Re: 1986 twin 50 hp popping out of gear

Is the Cavitation plate even with the bottom of the hull? Above, Below? Like this:<br /><br />

 

[cofused 50hp]

Re: 1986 twin 50 hp popping out of gear

thanks rick the diagram you are showing me is my problem. What I have decided is to go lower on the transom to bring it right in line with your diagram. This should fix my problem. Also to add to this would dophins help with the wash and foam

 

[OBJ]

Re: 1986 twin 50 hp popping out of gear

Cofused...try the boat first with out the dolphins after you drop the engines. If it takes a while to come up on plane, then add the dolphins.<br /><br />Nice pic Rick!

 

[cofused 50hp]

Re: 1986 twin 50 hp popping out of gear

thanks jim I will try this first. I appreciate all the help guys this is allot easier to brainstorm with many than one

 

[Dhadley]

Re: 1986 twin 50 hp popping out of gear

Try some fins before you cut the transom just to see what happens. Its easier. Then get rid of the 130 gallons in the nose of the boat. Thats the worst possible place to put weight. Get the tank empty and use another fuel source to test or at least get all but 6 or 8 gallons out and try it again.<br /><br />Good luck!