evinrude 2.6xp/235 running rich

[slikciv99]

Hello guys,

I have a 1985 evinrude 2.6xp that at some point someone replaced the block with an ordinary 235 block. I know the block isn't an original 2.6 because I've had it apart and looked at the porting. All of the ports are round. However, it has the 2.6 heads and they have been shaved .030 Compression is 125 all the way around. Here is my problem. This motor is on a bass boat and it runs great at full throttle, however if you throttle around for a while it will load up and it will hardly get on plane. Once its on plane it runs like a scalled dog. I've changed just about every electrical part (all coils, plugs, stator) I've got great spark. Here's my theory: I know the carbs on it have the jets that were on the 2.6xp. I'm thinking that the thing is running rich being that it doesn't have the porting that the original jets were ment for. Especially the idle jets. How can I make this thing run right? Anyone have any other ideas?

[EMDSAPMGR]

Comparing the 1985 2.6 jets with a stock 1985 235: The Idle jets: 2.6 uses .033, the stock uses .034. The mids: 2.6 uses .033, the stock uses .031. The high speed: the 2.6 uses .070, the stock uses .063. Normally, if you run a stock block, with the 2.6 carbs, you should be able to rejet it. However, you need to be very careful since your stock heads have been shaved and you are running an extra 10-15 lbs of compression. The carbs need to flow enough fuel to keep the pistons cool with those heads-esp at high rpm's. I'd wait in doing anything with the high speed jets and experiment with the idles/mids first. It is still possible that you are overfueling slightly with the .070 high speed jets.
Does that powerhead still have the original rubber intake filler blocks in it?

[slikciv99]

Yes, it has the filler blocks. It also has all of the 2.6 electrics including the 6200 rpm packs. There is one other thing. At some point someone shaved down (ported?) the inside of the intake covers (the 6 that are on the sides). I'm guessing to help flow. Would you recommend changing to the 235 idle and mid sizes?

[EMDSAPMGR]

It's good you have the filler blocks-helps with the crankcase compression. Probably won't see much difference when you change the idle/mids, but probably a good place to start. See what changes occur. Then get into the mains. Keep in mind that these engines run absolutely the best when they are too lean, so make sure you jet the mains on the fat side. Someone may have tried to polish/smooth the intake covers. They shouldn't get cut/shaved much at all, as they also act like the intake filler blocks-they take up useless crankcase volume and increase flow rates.

[slikciv99]

Ok, I'll order up those idle and mid jets and see if it helps. I do have another set of intake covers that are not altered. Would it be a good Idea to put these on instead of the cut ones? Thanks for your help.

[frank jackson]

I would be checking the recirculation system before rejetting .

[terry taylor]

I would be checking the recirculation system before re jetting . Yes I agree. Are you using a heat range of br8? Are carb. floats to high? Using synthetic oil at 50-1? Try larger air bleed jets, 2or 4 thousandths, but coughing at idle is too lean.And above all some of this is attributed to the nature of the beast [technology] thanks.

[Forkin' Crazy]

XP? GT? If you have had it apart, does it have the scalops in the pistons and coninciding porting in the cylinders?

BTW My 2.6 GT had 125-128 with stock uncut heads.

Running rich can be caused by improper float setting or jetting. As far as the mids., 2 sizes richer on the mids equates to 1 on the mains.

[Riverman]

If you have had it apart, does it have the scallops in the pistons and coinciding porting in the cylinders? I'd like to see a picture of that.

[racer]

The 2.6 carb is also slightly different than the 235, part of the jetting difference. Does trim angle effect the idle?

[slikciv99]

Yes, racer, if you tilt it lower than level it lowers the idle. more and more the further you go down. Actually, I believe it raises if you tilt it up too. I remember setting the float level as the carb is upside down.

[slikciv99]

Forkin, it definitely does not have the scalloped pistons. This is a 235 block that has all of the 2.6 parts put on it. The ports are round not square also.

[slikciv99]

Terry, when you say heat range you mean plugs, I have champion ql77jc4 in there. Carb floats are set level when upside down. Yes, 50-1 synthetic.

[slikciv99]

I would be checking the recirculation system before rejetting .

Frank, I don't know what you mean by recirculation system. The intake doesn't have the recirculation hoses that later models have. However, I do have one I could put on there if that would help.

[EMDSAPMGR]

The correct plugs for that engine are: UL77V (comes with this plug from the factory.) or UL16V

[slikciv99]

The correct plugs for that engine are: UL77V (comes with this plug from the factory.) or UL16V

Are those the same heat range as the QL77JC4 but just surface gap? I'm willing to try anything at this point. I just want it to work better.

[frank jackson]

The recircultion valves are on the intake manifold and its to take excess fuel and oil that puddles in the intake and sends it to the maine bearings on the 2.6 . The early 235s sent it to the transfer covers .

[terry taylor]

Terry, when you say heat range you mean plugs, I have champion ql77jc4 in there. Carb floats are set level when upside down. Yes, 50-1 synthetic.

Yes it,s the ngk preferred heat range number, someone correct me if i,m wrong brh 8 these are the extended electrode [not surface gap. At idle and low speed they help for less plug fowling and better idle thanks

[racer]

NGK cross to a 77JC4 is a b9hs-10 an 8 would be one range hotter. If trim effects the engine I would lean the idle 2 numbers

[slikciv99]

NGK cross to a 77JC4 is a b9hs-10 an 8 would be one range hotter. If trim effects the engine I would lean the idle 2 numbers
Racer, I'm having trouble finding the omc part number for a #35 idle jet. Can you or anyone help me out. Also, where is a good place to buy jets? I ordered from boats.net and half of the jets were the wrong ones. Thank you

[EMDSAPMGR]

318832 is the part number for a .035 jet. Many factory service manuals have a two pages listing of jet sizes in the section 1, the General Information section. You can get the jets from any Bombardier dealer.

[ChrisCarsonMarine]

Installing a manifold and transfer port covers with re-circ fittings will help a lot in my opinion.Without it the motor I'll load up with puddles of oil...on accelleration the oil is picked up and thrown into the mix,flooding the motor.Check or replace the reeds with the manifold,leaky reeds don't help a bit.My 235's accellerate just fine...keep looking,you'll find the trouble.If you need the manifold and covers with bleed fittings,and of coarse reeds,I have plenty on hand,Chris

[Riverratt]

a 1985 intake would have the recirc hoses on the intake but not on the bypass covers.

[slikciv99]

a 1985 intake would have the recirc hoses on the intake but not on the bypass covers.

The intake on this engine does not have any recirculation hoses on it. I have an intake that does have the hoses on the intake. Would this one be better than what I have?

[ChrisCarsonMarine]

Yes but you need covers to match,chris

[Forkin' Crazy]

The recircultion valves are on the intake manifold and its to take excess fuel and oil that puddles in the intake and sends it to the maine bearings on the 2.6 . The early 235s sent it to the transfer covers .

Actually it does not. The two mains get oil where is pools on the bottom of 1 and 3 cylinders with coinciding check valves.

The early X flows used the bypass covers and the later used only the intake for recirculation.


Yes but you need covers to match,chris

Or just a later intake.

[Riverratt]

Not with the 1985 intake. It does not go to bypass covers and works fine
http://i277.photobucket.com/albums/kk77/Riverrattralph/IMGP0528.jpg

[slikciv99]

Ok, I have an unexpected find. I went to change out the idle jets expecting to find #33's in there. I found #36's....... So evidently who ever had this engine before me was trying to fix the same problem... So now I'm back to square 1. I still intend on changing the intake to one with recirc hoses. any other ideas? Maybe I'll wait to change the jets after I change the intake. I have an intake just like the pic above I can put on. Thanks for that pic.

[racer]

If you have an intake like the one pictured above you have recirc now, make sure the valves are good. I personally like sending excess to the passage way between the mains.

[slikciv99]

If you have an intake like the one pictured above you have recirc now, make sure the valves are good. I personally like sending excess to the passage way between the mains.

Racer, what I meant by I have one like the pic is that I have an extra one that has the recirc valves. The one on the engine definitely does not have them.

What do you mean by sending the excess to the passage way between the mains?

[slikciv99]

A little update: took the intake off to put on the other intake with the recirculation hoses and several of the fiber reeds I installed in there last season were chipped and cracked. I'm sure allowing excess fuel to flow. Im sure this is part of my problem. I'm pretty sure this motor has never lean sneezed. What else would cause failure of these reeds in such short amount of time? I bet it doesn't have 20 hrs on these reeds.

[ChrisCarsonMarine]

In my experience reeds can be damaged by lean sneeze or running with retarded timing causing intake backfire,the same backfire caused by chopping the throttle at high speed,with ir without a load,Chris