What Is Involved In Converting An Evinrude 150 Intruder Into A 175 Intruder?

**TNFISHRMAN** · 10-16-2003, 08:30 PM

I was just wondering what all I would have to do to convert an EVinrude 150 Intruder into a 175 Intruder. I had what I thought was a reputable mechanic tell me all I needed was 175 Intruder Carbs. and Throttle Body then do the bolt up and re-tune for a 175. Let me know what you guys think. Thanks, Lynn

**Superdave** · 10-16-2003, 09:02 PM

a similar question. Are you Joe?
DAve

**TNFISHRMAN** · 10-16-2003, 09:15 PM

Wasn't me Dave. My name is Lynn

**Bill Gohr** · 10-16-2003, 10:34 PM

the 175 has higher exhaust ports everything else is the same except the main jets, carbs are the same, just the jet.

**racer** · 10-16-2003, 11:35 PM

!75 also has a slightly tighter head.

**Bill Gohr** · 10-17-2003, 09:10 AM

I must have been mistaken (I doubt it) they are the same part number. 338311?

**Rowdy** · 10-17-2003, 09:21 AM

Guys

Now I don't know what MY motor you have but there are the new carbed motors for instance that do have a bigger carb throat. Seems like its about 2.5mm or there abouts... The heads do have a different squelch to them as Racer pointed out as well and was pointed out the port height difference of about .015"...

Now on the brandy new carbed Johnson motors you will find the bigger carb set on the 150. Go figure LOL...Make way more up with the difference in the heads. The bad thing here is the heads don't have a part number on them to know which is which. They do have a vendor casting number which means nothing really as the machine work is done to make the changes at the plant and a yellow or white dot is put on them to keep them straight. Bad thing is when the guys in the field get these all in the same parts washer the dots melt away, then you get the heads mixed up; motors are not running like they should after that...

Now a little more on the carbs too, there is different ones on the length of the mid-section also for the 150, 3 complete different sets for the 150 and the different mid-sections,not the 175...Now there are different carbs and different throttles on the 150. Not sure on how long this was the case for all the extremes that there has been put in place now but I do know the 99 MY's and up are for sure...There will not be anything as simple as bolt on this and have the 25 Hp... At least with stock OEM parts change out... Even if you was to get the 175 throttle bodies and carbs, and heads you still have sleeve work to do on the ports...

**Rowdy** · 10-17-2003, 09:27 AM

Bill

Posted while I was LOL...There are different heads if you check you will see 337548-150; then there is 338082-150JL; then there is 338311-150GL and SL... Then there is 338311-175...Hope this will help the mess all this can cause...I guess I should add that there is two different blocks for the 150's also...

**Bill Gohr** · 10-17-2003, 10:00 AM

is what is the difference between the 150 Intruder and 175, not jets or EL's. The head info you gave is correct for all the other models, and as you and I stated, the 150 and 175 GL's (Intruders) is the same. We all know there are various carb STYLES over the years for different low and mid range calibrations, but there are only 2 venturi sizes. The small ones go on the EL's and the bigger ones on the GL's 150 and 175.

The Eagle blocks also had various changes over the years, this not noted by a paint mark but the letter stamped on the exhaust casting near the serial plug. And yes, in a given year as you said there are 2 150 blocks, the 150 EL and the 150 GL.

If TNFisherman has a given year 150GL and wants to convert it to the same year 175, you raise the exhaust port 2 degrees and change the main jet to the same year 175, thats the actual difference between the motors in that same year. The 150 makes peak power at 5400 and the 175 at 5700.

TN keep in mind the actual difference in these 2 engines is only 10 to 12HP, you will gain a little top end but you will lose bottom. On a heavy boat it is better to have the 150 for the low end.

Rowdy, I was keeping my post short and sweet as not to confuse him.

**Rowdy** · 10-17-2003, 10:13 AM

Bill

Sorry to have messed the short and sweet post up for you LOL... Also for confusing anyone on this matter...

**Bill Gohr** · 10-17-2003, 11:12 AM

Your information is good and correct, I've just seen too many times on the board where too much info is given in a situation that can confuse someone. That's why I'll just try to keep things short and sweet.

**TNFISHRMAN** · 10-17-2003, 07:14 PM

I had my mechanic which was an old drag boat racer and Omc trained and certified tell me that all I needed the 175 Carbs. and Throttle bodies to do the conversion. My motor is a 1997 Evinrude E150GLEU Intuder. From What I'm seeing bolting on the Carbs. and Throttle bodies I am not going to see a difference. Bill, What do you mean by raise the Exhaust port 2 deg.
Also, if I can find a 1997 Evinrude 175 Intruder it should have the same heads as my 1997 Evinrude 150 Intruder right? The Intruders are supposed to be GL's. Will the Exhaust ports be the same?
What can you do to get more H.P. out of the 150 Intruders(E150GLEU)? Guys I appreciate all the comments, keep them coming I am trying to make an educated decision.

**racer** · 10-17-2003, 08:49 PM

Now that we know what year the engine is Bill and Rowdy are correct but yes Bill you are mistaken if it had been a 92 or 93 as they used a different head on the 150 and 175, from some reason all 150`s got the same head, the intruders did not get the 175 head which is slightly tighter than the standard head, this is a good example of model number importance when asking specific questions. Bill kind of like the H suffix 1981 235 hard heads?

The carbs/throttle bodies you will find have different part numbers do to jetting differences, how ever your model also has a different part number body only, this is an empty body with out jets and float bowl, often this is different for idle and mid calibration as Bill mentioned, in good tune very little performance difference between the 150 and 175 intruders.

**Bill Gohr** · 10-17-2003, 09:26 PM

The port timing is done in degrees of crankshaft rotation. If you had a degree wheel on the crank and set the piston at the top edge of the exhaust port, and then set zero, then rotate the crank so that the piston moves up 2 degrees on the wheel and mark the cylinder wall at this point you would see how much higher the port is on a 175. In 97 the 150 GL and the 175GL use the same carb assy's except for the main jets which if I remember correctly was 2 numbers higher, look in a part book for that year. The heads are the same part number. 338311

Your drag racer buddy is incorrect on needing carbs.

**TNFISHRMAN** · 10-18-2003, 06:46 PM

Bill, I just wasn't sure if you meant port side timing or if you meant the exhaust port itself needed machining 2 deg. . So all in all I would only have to have 175 Throttle bodies and change the main jet and raise the port timing 2 deg.???? Thanks