Update to 1985 150 Johnson rebuild.

[h_lankford]

Re: Update to 1985 150 Johnson rebuild.

I am not an expert, but have been following your exploits with interest.

Here is some logic I hope is correct and useful.

The BRP catalog says high speed metering orifice (actually not a jet) for your motor is 55C (standard). So if they took out 56C (why was that in there?) and put in new 55C, then you should be running leaner with the 55C than with 56C as is appropriate for higher altitude where you need less gas for less air. Maybe someone can tell us what orifice to use at 6,000 feet, but bogging sounds lean, so larger orifices might be needed for your rebuilt ( ie different) engine.

From my reading on this forum, a 2-step change in orifice is significant, so if your is only 1-step different then that is minor and therefore not the source of your major bogging.

 

[emdsapmgr]

Re: Update to 1985 150 Johnson rebuild.

They made two types of 150's that year, the base 150-model 150T which uses 55 jets, and the GT-model 150ST which uses 58 1/2 jets. The GT model uses the larger carbs, which get larger jets. Knowing where you should be depends on which carbs you have on the engine. What is the model number of your engine? The jet sizes for both engines are close enough, however, that it should run over 2000 rpm. There are low speed jets, mid-range and high speed jets. Can you identify for us what you have in all three? What pitch prop are you running on it now? When it bogs, try hitting the choke (fuel primer)-that will inject extra fuel and it may pickup or bog-post your results.

 

[firemann2003]

Re: Update to 1985 150 Johnson rebuild.

I have the J150TXCOS. Low Speed Jets = 33, Mid-Range Jets = 29 and High Speed Jets = 55C. Current prop. is a 15 x 17. Hitting the primer solenoid does not stop it from dying, nor does pumping the primer buld. Have a clear fuel filter inline right before the lines go into the engine and it stays alittle more than half full of fuel when the boat is running.

 

[mikesea]

Re: Update to 1985 150 Johnson rebuild.

Update a bit.You say in one of your earliest posts,that the engine ran perfect.Is that right,no problems. ?Then one day you went out and it ran bad ,over 2000 rpm.Is that right. ?Then you changed the VRO pump?ran better ?IBut still stalled over 2000Are you sure the vro is getting enough crankcase pressure. The nipple from the crankcase and hoses are not full of crap,are they,theres a check that goes in the line from the crankcase to the vro ,is it properly installed.F.Y.I. I have a vro on my 150,and noticed that there is NO check or fitting,just a hose from the crankcase to the VRO, I know you rebuilt the engine. Did you ever change the statorYes no?Do you run mixed gas now,did you disconnect VRO.If you disconnected VRO,are all wires diconnected.I agree with you that it must be a gas prob.If the motor ran perfect day one. What was changed if anything.Same boat,prop,your jets and all worked day one and I kinda believe the prob. is too radical for that to be a factor.But then you say priming the ball dont help at all.If not the fuel,I am suspecious of the stator.I knowe your really bugged,because I'm stumped and keep thinking about this too. Post the answers.

 

[emdsapmgr]

Re: Update to 1985 150 Johnson rebuild.

Your base 150 engine has all stock jetting. Lows, mids and high jets are all to stock spec. I would not say any work was done for high altitude running. It's a little hard to say where to start, but will offer a suggestion. Take the boat to the lake and run it. Put a timing light on each plug wire. Run the engine up to 2200-till it starts to miss and see what flashes you get on each plug wire. Check all 6 plug wires for complete misfires or intermittent/sporadic firing. Hard to look for fuel problems till you know the electrical system is ok. Your 17 pitch prop should be fine.

 

[mikesea]

Re: Update to 1985 150 Johnson rebuild.

Hey,something else,I just remembered this replying to another post. I had a problem yrs back trying to run a 236 (v-6 crossflow) on a portable 6 gal tank. It seems the hose,connections etc.caused a restricted fuel flow to the engine at high rpm. Is this possible in your case. I tried a tank and hose for a 9.9.Didnt work. You NEED 3/8hose for a v-6.i'm digging in the brain

 

[firemann2003]

Re: Update to 1985 150 Johnson rebuild.

The time it seemed to run good for me was my first outing with this motor. Ran it for about 20 - 30 min. than that is when it completely died. VRO change got it running but not correctly.

Ok, here is one of my first good news posts, lol. Put a new 15x15 prop on, suggested by a mechanic that I have heard nothing but good things about from people around here. Also, now the part that makes me feel pretty dumb, put in new champion plugs (spec'ed in manual) gapped at .040 as per the manual. The ones that were in it were NGK, sold to me by the shiester mechanics that first worked on the boat for me, gapped at .026. When I changed them during the rebuild I just put in the extra set of new ones they sold me and never checked the gap, another lesson learned about trusting those guys. Now here is the good news!! Girlfriend and I took the boat to the lake, started like a champ, ideled like it was new, hit WOT with not so much as a minor sputter and planed out in about 15 sec. only left it there for about 30 sec. because break in not done yet. But it got there twice, continued to work the throttle up and down from idel to 4000 repetedly, for a couple of hours, with not so much as a hick-up.

Mike I was thinking that 1/4 may be to small, but that is what was on there so that is what I left on it. May go ahead and change fuel lines again anyway.

I want to thank everybody on here for all thier help. I probably would not have gotten this running with out you and would have spent a whole lot more money too, You guys are awsome!! Hopefully this thing will stay running and the trip to Lake Mead during Thanksgiving week will still be a go.

 

[firemann2003]

Re: Update to 1985 150 Johnson rebuild.

I am still running VRO to mix my fuel and gas. I temporarily am using two 6 gal portable tanks till I get the two new tanks mounted and plumbed.

 

[firemann2003]

Re: Update to 1985 150 Johnson rebuild.

I will post some pics. from the next outing so you can all see the results of your knowledge. Thanks again!