91 johnson 150 bogs down

[holidayjay]

hey guys, hopefully someone can shed some light on me with this because its frustrating

i have a 91 proline boat with a 150 vro motor on it. this boat hauls ***** at about 5700 rpm but the problem is it just wont get there. sometimes when i go wot the motor will choke down and stall. hitting the choke doesnt help either, tried pumping the ball..nothing. the engine will run fine for a while but it seems after about 20 mins of running it happens again.

the other day i was out on it testing it running some seafoam through it and it happened. i took it out of gear and put it back in and the motor stalled.start it back up and rev it in neutral and revs fine. put in gear and go wot the boat almost gets on plane then chokes down again.i took the engine cowl off and theres a solenoid (dont know if its a choke or some fuel valve) but the red valve on it is pointing away from the body of the solenoid. i turned it 90* and the boat now gets back up on plane but still wont go over between 4k and 4500 rpm. i moved the valve back to its original position and it bogs down again. if i move that valve so that it is facing down towards the body of the solenoid the motor wont run.

another thing is sometimes the boat will scream at 5700-5800 rpm and other times it will be 4000 and yesterday it topped out at 3500 rpm.interstingly enough i was coming back in from an island with my wife and kids on the boat and i couldnt get on plane at all..any amount of throttle and it would bog down so i pull the cowl off and turn that red valve 90* and it went but again only at 3500 rpm which is just enough for me to get on plane.

one thing i also noticed as well and maybe its just coincidence but it seems that rougher water makes it worse. maybe it is an issue where load affects it as well?


now for a little history..
so far i have replaced the power pack, put a different vro pump (i premix so the oil is blocked off since i heard vro stands for very rarely oiled)put fresh plugs and wires. my starter was missing a bolt and it used to loosen from vibration and the ground thats attached to the starter would cause the same issues that i described above but after fixing that the issues came back.
i ran seafoam through it ,replaced the water seperator and last week i went to pull my carbs off to clean them but after i got the top carb off it was so clean that i didnt bother with the others.
on the bottom of the airbox there is a vac line that goes to the manifold that i noticed on the vac nipple it doesnt seat very tight. could a small vacuum leak cause it to run that rich and cause those problems?


sorry for the book that i just wrote but i really need some help trying to figure this out.im almost at a point where i might just buy another motor but i had 90 compression in every cylinder and at 5800 rpm the motor is super strong so it might just be something small

what are you guys opinions? what can i check? maybe a stator or pickup?
im in holiday florida if there is anyone local that would be willing to help me figure it out i would forever be grateful!


thanks for reading
jay

 

[holidayjay]

Re: 91 johnson 150 bogs down

also and maybe its me but the other day this happened twice.. i was idling out of the no wake zone and as i come out i go wot and as the bow comes up it felt like i was slowing down although rpm was climbing...almost like a auto trans was slipping im no rocket scientist but i didnt see a trans on there lol. i did have marine place replace my broken upper mount.the day they fixed that they brought me down to the boat launch and had to bring me back because i had no gear. some bolt they didnt put back in was the cause anyway they fixed it and i was back on my way to my other normal problems. any chance maybe they screwed something up when that happened?

 

[ezeke]

Re: 91 johnson 150 bogs down

Turning the red handle on the primer soenoid keeps it on all of the time; that's for emergency starting only when your battery is dead and you have to use a rope. If you leave it that way, it will flood the engine when the engine is warm.

Otherwise the red handle should always be aligned with the cylidrical part of the unit so that you can operate it from the helm by pushing in the key.

 

[holidayjay]

Re: 91 johnson 150 bogs down

Turning the red handle on the primer soenoid keeps it on all of the time; that's for emergency starting only when your battery is dead and you have to use a rope. If you leave it that way, it will flood the engine when the engine is warm.

Otherwise the red handle should always be aligned with the cylidrical part of the unit so that you can operate it from the helm by pushing in the key.

when it is up (aligned but facing away) it operates when you push the key in. i read that some of them are backwards where up auto and down is manual. do you think this is unrelated to my problem? what i dont get is when its turned halfway the engine runs better. maybe its running lean? th plugs dont show it though.. could it be possible my vro pump is no good? should i convert it to electric pumps?

 

[holidayjay]

Re: 91 johnson 150 bogs down

ideas? anyone?

 

[jonesg]

Re: 91 johnson 150 bogs down

Problem being you don't know whether its fuel delivery or electrical (ignition)

Baseline it,
do a spark gap test,it should jump 7/16th inch,
then take a timing light when you run it on the water,
see if its dropping spark,

check temp when it acts up.

Test run it with a temporary portable tank,
eliminate any water seperators and filters for the test.

 

[holidayjay]

Re: 91 johnson 150 bogs down

Problem being you don't know whether its fuel delivery or electrical (ignition)

Baseline it,
do a spark gap test,it should jump 7/16th inch,
then take a timing light when you run it on the water,
see if its dropping spark,

check temp when it acts up.

Test run it with a temporary portable tank,
eliminate any water seperators and filters for the test.

ok thanks for the ideas, ill see if i can find someone that has a small tank that i can try. as far as spark goes i can test it with a timing light but i dont think a spark gap test would do any good though honestly...it runs fine at idle and at wot sometimes. the only time it acts up is at wot.

is ther a way you can bench test the stator? i wonder if maybe one of the magnets on the flywheel possibly cam off or something like that. is there a way to test the pickup?

 

[holidayjay]

Re: 91 johnson 150 bogs down

another question.. and btw you guys are awesome here!

my boat is a 91 proline 18'6" cc it has the 150 on it now, if i were to repower it how do i find out what the max is on the hull? can i put a 200 on it?

 

[holidayjay]

Re: 91 johnson 150 bogs down

i wish my credit wasnt screwed i would try and finance a new one

 

[jonesg]

Re: 91 johnson 150 bogs down

Fall back and regroup . you still haven't sorted out whether its fuel or electrical

Baseline it, get a gap tester for $6.
No test tank needed, engine isn't running when gap testing spark.
It must jump almost 7/16ths inch to pass/fail.

If its ignition....
To test stators and powerpack get a dva adaptor for a multimeter and do the tests here for hi-speed miss.
http://www.maxrules.com/fixomcoisignition.html

 

[emdsapmgr]

Re: 91 johnson 150 bogs down

Take the boat for a spin with a friend and an inductive timing light. When it starts to crap out, check each plug wire for spark when under load. You will get a good idea if they are all firing, or intermittent or not firing. If you have great spark on all 6, you can think about a fuel problem.

 

[holidayjay]

Re: 91 johnson 150 bogs down

thanks for the replies guys.. i havent had time to do anything with business picking up(thank god) . ill be gone on business till monday but when i get back tuesday ill check that stuff. appreciate the replies

 

[holidayjay]

Re: 91 johnson 150 bogs down

ok time to beat the dead horse again...

i havent had time to mess around with the 4 letter word b**t but im gonna go down today and mess with it.

last week i tried to use it and things went awry. i came out of the no wake zone and as soon as i hit the throttle it died like a pig. i couldnt give it any throttle at all. i threw out an anchor and started checking things.first thing i noticed was the ball was empty. i may not be a smart man but im pretty sure you need fuel to run. when i was trying to pump it it felt very mushy..maybe there was a restriction. i took off my water seperator to check to see if there was water in there and there was some. i dont recall ever looking in it when it was new but there was some brown colored hard stuff in there like a glue or something...i dont know if maybe thats supposed to be in there or what,does sediment harden in there or something?

after a little while i was able to get it started (not sure what i did) but we headed out to an island and it died down again.the fuel ball was fine so i pulled the engine cover and started looking around.a couple months ago a guy replaced my top mount and he had cut a bunch of wires to remove the powerhead. i notice where he connected them he used butt connectors and i saw some corrosion on there.one of the wires iirc was a white wire going to the power pack. im going to go down and rewire whatever is corroded today. ill bring some wire and solder and heat shrink everything.

i have a feeling the guy who worked on the boat created some extra problems for me. when i first got the boat back i had my wife and kids on the boat and we got up on plane and the boat made a quick left turn out of the channel and almost into a sand bar.i looked down and the nut for the steering linkage was left off..... i try to let things roll off my back but i was really ticked to say the least

 

[holidayjay]

Re: 91 johnson 150 bogs down

well heres some closure..

went down and fixed the wiring and took the boat out. ran great.. motor ran 5600 and smooth so packed it up and planned to take the wife and kids out to an island and hang out for fathers day. got about halfway there and it overheated and im guessing blew the motor. i let it cool down and it started however it will only run in neutral after many attempts. im guessing theres no compression because its not getting fuel..boats suck

 

[rick74631]

Re: 91 johnson 150 bogs down

have you check your fuel line mine did the same thing did every i new to it i check the fuel line on the carbs and found one was sucking shut on me when i took off i replace both of them and it now runs good hope this helps

 

[holidayjay]

Re: 91 johnson 150 bogs down

have you check your fuel line mine did the same thing did every i new to it i check the fuel line on the carbs and found one was sucking shut on me when i took off i replace both of them and it now runs good hope this helps

i put a test tank on it to see if it was fuel or ignition and it actually worked fine on both the stock tank and the shop tank. its a vro so it works off engine pulse so if i have low compression now due to the overheating it wont get fuel i believe

 

[ezeke]

Re: 91 johnson 150 bogs down

The pulse for the VRO works off the backside of the piston, so a blown cylinder head gasket will not change the VRO operation at all; it will cause the rest of your symptoms.

 

[holidayjay]

Re: 91 johnson 150 bogs down

The pulse for the VRO works off the backside of the piston, so a blown cylinder head gasket will not change the VRO operation at all; it will cause the rest of your symptoms.

i have to give it a compression test and see where im at.. i dont know if whatever happened is catastrophic yet but maybe it is just a head gasket...man i hope so. how hard is it doing the heads on a 91 johnson 150?