1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

[concord22]

Hello. I'm having problems with my 200hp looper & was hoping someone has a logical resolution for it. First off the oil injection has been bypassed & I'm running a 50:1 mix.

Heres what I know: The engine starts right up, Idles nice and runs great all the way to the red line on plane. But... now the catch... The engine has to be trimmed up enough so it can breathe. which sucks for a multitude of reasons.
The problem comes in with the engine trimmed down. it will start but imediatly die, or will bog out completely if you try to put it on plane. Yes the engine does sit low in the water. the exhaust reliefs are about 1 1/2"above the water line.

I read a post about johnson putting 1987 carbs on 1988 motors to cure this but what if anything can I do to cure this problem on a 1987?
Any input would be greatly apreciated!!!

oh ya! its mounted on a 1988 22' concord Magnum.

 

[j_k_bisson]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

When is the last time you cleaned you carbs? I bet that a good carb servicing will fix this condition. You have no other issues with this motor? The tach is working fine?

 

[James R]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

I concur on the carb cleaning. No spray cleaner, do the job properly or burn up cylinders.

 

[concord22]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

Thanks but the carbs have been gone thru twice. once by myself. I'm very versed in carberators and was an ASE master tech for 12 years though i'll admit i'm new to outboards but carburation is the same and i did spend the money to have the carbs gone through by a certified shop just to prove to the guy i bought the motor from that it was done correctly. The engine definatly does not starve for fuel. I say this because when it boggs down it loads up and it will show on the plugs as they started to foul halfway through the season. I've run this boat all season almost every weekend on lake michigan from milwaukee to chicago with no problems as long as its trimmed up when not on plane. it just seems to struggle to breathe as the motor sits so low in the water but the exhaust reliefs "for lack of the proper term" are above the waterline at all times.

There are no tach problems. Once on plane I can run it into the red line effortlessly with a 23 x 17 steel prop. this is a
22' concord magnum weighing about 2,600 lbs without persons or gear.

I know this is lengthy but I wanted to answer your questions as best as I can.

Repairs done so far by myself but mostly certified shops: carb cleanings, spark plugs, one reed valve replaced, new flywheel, 1 CDI box & it runs the same as the day I bought it.

Any other Thoughts would be apreciated.

 

[boobie]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

Has this been a problem with this boat/mtr combo since day one?? IMHO I think it's to low in the water.

 

[concord22]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

@ boobie
Yes it has been a problem since day one. I bought the motor and boat seperatly and set it up. I feel the motor is to low in the water line but i can not raise it's mounting because then it will cavitate. I have the cavitation plate about 1 1/2" above the keel as of now and still get some cavitation around 65mph so raising it conventionally is not an option. ideally i'd like to lower it to solve the cavitaion problem. Idk....Thoughts?
and whats IMHO meen? lol

 

[concord22]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

@boobie
Btw: I thought about an exhaust housing from bob's machine shop but really don't want the extra noise & thought perhaps there might be another reason its not breathing well.

 

[boobie]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

IMHO=in my humble opinon. I hate to tell you this but I think you don't have enough flotation in the boat for the size of the mtr. I've seen this happen to many times over the years especially with Sea Drives. If you have it on a trailer, tie the boat down good and take it to a landing and back it into the water with the mtr down until the exhaust reliefs are about 4-5 " out of the water and see how it runs.

 

[jeffersondodson561]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

Whats red line to you?

 

[concord22]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

Thanks boobie! thats solid advice & I agree with you about the floatation the puzzling thing about this is that concord still make these boats with no visable design changes. They even post a picture on their web site of one thier smaller models with a 300hp merc. pehaps they've changed some boyancy caractoristics or the new motors are lighter. not sure. if it does infact run well on the trailer in water as you described would you have any suggestions to save the project in a practical manor other than a power lift plate?

 

[concord22]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

whatever the Red line on the tach was. If memory serves me correct was 5500 possibly 6500 & has gone effortlessly higher than the red on the tach with a 19 pitch prop. Its been since october since I've seen the tach tho. its about 5 deg outside here today. lol eitherway the motor was spun pretty tight by my standards. but I'm new to outboards. thoughts?

compression was checked at the start of this problem & all cylinders were pretty even. cant be 100% but thought the numbers were in the 120's.

I would hope the shop i took it to adjusted the timing as needed after the flywheel was changed. its not advanced for sure. it never grumbles under load. i suppose it could be retarded but again i hope they checked it. but thats something to look at again.

 

[concord22]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

Oh and I've never put a wide band on it. but as far as I know the jetting is stock. could running the oil mix through the carb jets effect the a/f enough to cause problems? as i stated before the oil injection was bypassed by the previous owner & the repair shop I took it too was aware of this & had no negative comments.

 

[metriccrescentwrench]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

I'd suggest getting an OMC factory manual (if you don't already hove one) and painstakingly follow the instructions for a link-n-sync. Idle is best adjusted with the boat in the water, so it's possible your engine had been set up for a situation where it had a lot less back pressure at idle. You may be able to get away with just bumping up the idle timing a few degrees, but to really do it right you'd want to follow the entire procedure.

(PS - if you give up on that engine and part it out can I have first dibs on the heads ?)

 

[James R]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

I have rebuilt several johnrudes up to 150. Some of them did not like extra oil that was necessary for break in and had problems similar to yours until I reduced the oil to 50:1. Just a thought.

 

[jeffersondodson561]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

There are no tach problems. Once on plane I can run it into the red line effortlessly with a 23 x 17 steel prop. this is a

23" diameter prop!! Take a picture of this please with a size reference beside it, and post it. This could be the problem right there.

 

[mekkamaz]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

23" diameter prop!! Take a picture of this please with a size reference beside it, and post it. This could be the problem right there.

...X 2! I was running my chris craft scorpion 217 (21.7') with a Johnson 235 and a 21" prop......

 

[j_k_bisson]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

Well I'll chime in here. These motors's do have quorks. I have the same motor, but it is a bit of a Frankinstien though, I started out with the prop pitch you have on as 21' Trophy WA boat and had to drop down the pitch of the blades due to low to mid range engine loading. I'm currently at 15" pitch prop and all this has cleared up. These carbs are fixed jetting for idle and mid range unlike older and newer carbed modeled Evinrude motors.

It could be the Jets need to be played with. There has been lots of talk about this on here by most of the guys that chimed in here.

It also could be any other thing. I personally struggled with the motor height when I installed mine. I had it even with the tip of the keel and eventually raised it up 4 holes, 4", to get it right. Now I am *** end heavy on my boat with a motor that is a bit over rated for the boat. 50 hp or 100lbs. This could be also your problem. Your boat sinks when you are not up on plane, this would cause over loading of the motor at low speeds. I over came this with adding weight to the front of the boat. I do not recommend this to anyone, by for testing, you might want to add pails of water up front and see if it makes any kind of difference. I found 5-5 gallon painls of water made a huge difference in the motors operation at low speeds. It did not load up as much. But in bigger 6'-10' I liked the *** end heavy.

The last thing I am doing to mine this spring, I'm planning on replacing all the spark plug wires. I want to switch them over to the Accel 8.8 wires. Don't like the fact that I am using 20+ year old wires on an outboard that has brand new electronics and wiring. Just does not seam right to me. Wires have come along way in that time. Might want to check yours out.....

Just some thoguhts, hope they help......

 

[jeffersondodson561]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

...X 2! I was running my chris craft scorpion 217 (21.7') with a Johnson 235 and a 21" prop......

No what I am saying it that if you are reading the writing on the prop from left to right, the first number is the diameter (23") which in my oppinion is way to big. Then the second number is the pitch. Larger diameter props are made for heavy (almost displacement hull) boats. I was thinking of more like a 14" (approx) diameter prop.

 

[concord22]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

Sorry I must have typed that wrong. its a 23 pitch prop.

I do have a manual for this & did review the timing procedure. was a bit confused if I should be doing this with the prop on or off tho... its been a while since i read the procedure.

I've ran the motor at 50:1 since ive owned it.

I did read an interesting forum on the carb bowls on these motors. supposedly they warp and cause an excessive amount of fuel to enter the engine. I have noticed a small leak from the bowl area " not the lines" while on the trailer. i assumed it was normal due to being in the transport position and bouncing down the road on the trailer. though might not be a bad investment to replace the bowls and needle and seats.
I apreciate everyones thoughts and advice. My plan of attack will be as follows. First I will be rebuilding "not just cleaning" the carburetors with new float bowls, then I'll see how it runs on the trailer in the water on the boat launch with the exhaust reliefs above the water line where it would sit normally in the water. if no improvement is noticed I will then try it with the engine 3" higher by moving forward on the boat launch. If an improvement is gained I'll assume its an unavoidable set up issue with my boat and motor combination & install a exhaust housing from bobs machine shop & live with it. but if moving forward makes no differance I'll run the timing & sync procedure and continue trouble shooting. I'll post the results this spring. Thanks to everyone again. Your comments are still welcome.

 

[concord22]

Re: 1987 johnson 200hp looper bogs, poor idle, sits low when trimmed down

So i've been working on this a bit & I've only gotten as far as installing the exhaust housing from bobs machine shop. so no water tests yet "launch still closed"

My terminalogy was wrong on one of my posts. I'm experiancing "chine walk" around 65mph not cavitation. This engine has a good 10mph more in it. I'm seriously doubting the install hieght is correct. My motor is mounted on a 12" set back. I was told the cav plate should be aprox 1 1/2" or so above the keel as a starting point. but now I'm reading it should be higher if you're using a set back.
In the past I've been 2 mount settings higher but experianced cavitation "engine rpm spiked" when the boat first dropped on to plane. Any recommendations on a good performance & set up book? I'm getting frustrated with reading conflicting recomendations online.
my lack of experience does not help...