86 johnson 150 gt vro will not plane......

[nogo]

hello all i'm new here, just lookin for some advice. i have an 86 johnson that wont plane when under load. had it to the local boat shop for service and the tech rebuilt the carbs changed some fuel line and filter replaced the coils. said the engine runs great in the tank but when he took it to the lake to test it boggs about like it only has half throttle when its opened wide. the tech says it may be the stator ring or power packs, any other suggestions? also the tech says the compression is fine and suspects its an electrical problem.

 

[jdupree]

Re: 86 johnson 150 gt vro will not plane......

Just had the same problem and it was the power pack. Motor is a 1988 90hp Johnson.

 

[wreckless]

Re: 86 johnson 150 gt vro will not plane......

Why did he rebuild the carbs? Was that something that you wanted or was it a fix for an earlier problem? If you had the problem before and the mech rebuilt the carbs and then tells you it may be the power pack I would take it to a different mech. You can test the power packs. If a power pack goes bad you will loose power to the three cylinders on that side.

 

[hookedonjc]

Re: 86 johnson 150 gt vro will not plane......

Check out my post I had several problems. And finally found short in wire going to the S.L.O.W. function I dont know if you have the S.L.O.W. but it will reduce your RPM its a safety feature for over heating I also found a problem with VRO fuel pump.
Good Luck

Dont Ever Give Up

 

[nogo]

Re: 86 johnson 150 gt vro will not plane......

Check out my post I had several problems. And finally found short in wire going to the S.L.O.W. function I dont know if you have the S.L.O.W. but it will reduce your RPM its a safety feature for over heating I also found a problem with VRO fuel pump.
Good Luck

Dont Ever Give Up

from what i was told by the tech that worked on my engine he says the vro is working fine. as far as the power packs is there anyway to really test them? i know the plugs have spark cause i checked the 2nite. dont really want to get new packs if these are alright. as far as the s.l.o.w. feature in not sure my engine serial # is j150stlcdc if that helps anyone.......

 

[nogo]

Re: 86 johnson 150 gt vro will not plane......

Check out my post I had several problems. And finally found short in wire going to the S.L.O.W. function I dont know if you have the S.L.O.W. but it will reduce your RPM its a safety feature for over heating I also found a problem with VRO fuel pump.
Good Luck

Dont Ever Give Up

from what i was told by the tech that worked on my engine he says the vro is working fine. as far as the power packs is there anyway to really test them? i know the plugs have spark cause i checked the 2nite. dont really want to get new packs if these are alright. as far as the s.l.o.w. feature in not sure my engine serial # is j150stlcdc if that helps anyone.......

 

[nogo]

Re: 86 johnson 150 gt vro will not plane......

from what i was told by the tech that worked on my engine he says the vro is working fine. as far as the power packs is there anyway to really test them? i know the plugs have spark cause i checked the 2nite. dont really want to get new packs if these are alright. as far as the s.l.o.w. feature in not sure my engine serial # is j150stlcdc if that helps anyone.......

 

[OBJ]

Re: 86 johnson 150 gt vro will not plane......

Here's a simple test...with the boat in the water under way, idle would be good, start pulling plug wires. Look for the ones that DON'T make a difference in the way the engine is idling. The spark at each cylinder should jump a 1/2" gap with a hot lighting like spark. Testing by grounding a plug against the block really don't tell you anything about the ignition system.

What rpm are you at at WOT? Are the thottle plates all flat open at WOT? Did the wrench check the link and sync?

There are simple cranking test with a peak reading volt meter that can be done on power packs to make sure they are working.

 

[nogo]

Re: 86 johnson 150 gt vro will not plane......

wrench said under load wot was only 3300 rpm. havent had the boat in the water since but planing on it this coming week. put the muffs on today to test the packs and tell me if this sounds right but i pulled the wires off each coil from the pack to see if there was a noticable miss in engine and the port side there was no difference but on the starboard side there was. would i be right in assumming the port has a bad pack? as far volt testing them how exactly do i do that since my public library has the manuals but they are checked out at this point. would a standard multi-meter do the trick?

 

[emdsapmgr]

Re: 86 johnson 150 gt vro will not plane......

Your engine has two power packs, each feeding one side of the engine. Try swapping the power packs. If the trouble moves to the other side with the change, you have your answer-replace the bad pack.

 

[nogo]

Re: 86 johnson 150 gt vro will not plane......

ok took the boat to the lake today and tried to run it wide open and got about 3000 rpm on wot. while the engine was at idle i pulled the plug wire on each side one by one and got to the port side lower cylinder and the was no noticable difference in the idle but on all other cylinder the was a noticable miss. power pack? also while ildeing i opened the throttle by hand to see if rpm would increase.....took it up to about 5000. since i'm no mechanic would it be normal for the engine to rev up that high in neutral and not in gear? why the difference under a load.

 

[Walker]

Re: 86 johnson 150 gt vro will not plane......

Do a compression test

 

[nogo]

Re: 86 johnson 150 gt vro will not plane......

what is proper compression?

 

[nogo]

Re: 86 johnson 150 gt vro will not plane......

ok all cylinders are between 65 and 70 psi......

 

[emdsapmgr]

Re: 86 johnson 150 gt vro will not plane......

Among other possible problems, your compression is low. I would expect at least 90-95 on that engine. Did you take the compression with all the spark plugs out when you did the compression check?

 

[nogo]

Re: 86 johnson 150 gt vro will not plane......

nope only took one plug out ay a time...what would cause the low compression bad head gasket, wore rings, scored pistons??

 

[nogo]

Re: 86 johnson 150 gt vro will not plane......

also dont know how reliable this tester is borrowed it from my dad has to be at least 20 years old and it s a push in type not the screw in style

 

[nogo]

Re: 86 johnson 150 gt vro will not plane......

ok told you guys i was no mechanic did the comp test with all plugs out and they came back 85-90psi. seem right now? as for the timing mech told me it was good any other suggestions out there?