Need suggestions for v6 crossflow gt150 engine issue

[keefallan]

I just put this powerhead on my midsection. It is not modded. It's got the standard carbs and jets and porting. I used the boat yesterday and the boat didn't want to come out of the hole.....at all. It just died. I was trying out a 24 inch raker on my Ranger. When I finally got it going, it ran well. I then switched to a 19 pitched Ballistic so we could go skiing. I didn't know that I had motor issues yet.I went to stab the throttle and it fell flat....died. I re-started it and was able to get it going after a few tries and then it ran fine. Shortly later(getting ready to kneeboard), i found that when I choked the motor, it came out of the hole just fine! I did this everytime I stabbed the throttle...........no issues. Afterwards, I had me, my wife and 3 boys in the boat and headed home. I wanted to see what would happen. I was able to hit 57-58mph fully trimmed out @5600 rpm. If I brought it down to a troll immediately after that, it went right back up on a plane with no choke. WHat gives?

I did check compression this morning. It's all good 101 for the highest and 94 as the lowest. The powerhead is still new. I bought this from a builder in Florida that goes by the name SOuthXXXX MXXXXX. I do not ever recommend them to anyone. This was the 4th powerhead from them to get it right. I got this head in march. I have run it only 3-4 times. I actually expect compression to come up all around 100 shortly.

Besides the carbs being fouled(I'll go thru them later), what could be causing the issues? Is it the fuel pumps? I am running dual pumps. The timimg linkage is free moving and the timing is on. I have checked resistance on the electrical system too.

I was running my 235 on this setup with no issues with the fuel system. When I restored this boat, I put in all new lines and a new main fuel filter(spin -on) and I cleaned the fuel tanks inside and out. I really don't think it's anything related to the fuel system outside of the motor. I would love to hear everyone's thoughts on the matter.

Keith

 

[keefallan]

Re: Need suggestions for v6 crossflow gt150 engine issue

I forgot to mention that I am using re-built fuel pumps off of a 1982 235. I was the one who rebuilt them. I installed them exactly the same way they came off the donor motor.

 

[fishfeatures]

Re: Need suggestions for v6 crossflow gt150 engine issue

Besides the carbs being fouled(I'll go thru them later), what could be causing the issues?

Here lies your problem, if you have to choke it to get it going then your carbs need cleaning.

 

[keefallan]

Re: Need suggestions for v6 crossflow gt150 engine issue

I was going to go thru them. But here's the irony. I built them in march or april. I also fired the motor up at least once or twice thruout the season to keep gas running thru the circuits and not get all gummed up. Why would they gum up so fast? I ran this motor in the spring on my other boat with no issues. Since then, it did sit on a stand, but I ran the motor.

I figured if they were gummy, I'd see it when I open them up. I'm just suprised to hear that that is only answer. Thanks SENIOR CHIEF from over there in IRELAND

 

[keefallan]

Re: Need suggestions for v6 crossflow gt150 engine issue

I did also forget to mention that it WILL troll(not great, but it will troll). It just won't come up and out(except when I just ran it at speed).

 

[Faztbullet]

Re: Need suggestions for v6 crossflow gt150 engine issue

Choking it as your planing is a lean condition......causes: carbs low end circuits dirty, air leaks around intake( will also cause lean sneeze). The reason it will plane back off after coming off plane is that crankcase is still full of fuel charge from WOT running.

 

[keefallan]

Re: Need suggestions for v6 crossflow gt150 engine issue

Thanks for that Faztbullet. I don't have the time to tear into it today and I'm going out of town for the next few days. I have swapped out my intake manifolds between this motor and my ported motor. I wanted the boyesons on the ported motor. So, i DID pull the manifold off since I last used it in the spring. However, I did not have any sneezing. I did have to raise up the idle when I put it in the water(back pressure) versus home on the ear muffs. Actually, when I flushed it when I got back home, the idle was wayyyyyy high...1500 r's!! I know when it is running right I should get around 1100 at home and it will sit around 900 in neutral.

So, I'll take the carbs apart(I think they may be clean..we'll find out)since I will probably have to take the intake off(i'll retorque the fasteners first and spray starting fluid around it). I'll keep ya posted what I find. Thanks for making it plain about the lean condition. It forced me to look at it from a troubleshooting point of view(what is the reason for having to choke the motor)

Keith