Go Back  The Hull Truth - Boating and Fishing Forum > BOATING FORUMS > The Boating Forum
Reload this Page >

150 Ocean Runner - falls on face after trolling

Notices
The Boating Forum

150 Ocean Runner - falls on face after trolling

Old 05-12-2019, 11:18 PM
  #1  
Senior Member
Thread Starter
 
Join Date: Mar 2014
Posts: 219
Likes: 0
Received 19 Likes on 17 Posts
Default 150 Ocean Runner - falls on face after trolling

I'm trying to diagnose what I believe is a fuel issue on a carbed 150 ocean runner on a 18 Wellcraft Fisherman.. I've only run this motor 5 times so far on fishing trips, so I learn a little bit more each time out. Prior to the issues below, I had rebuilt the lower unit, and rebuilt the carbs.

Trip 1 - I experienced heavy motor vibrations and a top speed around 28mph. I had a crappy chewed up prop on there causing the vibration. I ran about 5 miles, anchored, fished, ran 5 miles back. No problems other than the vibrations and low top speed only hitting about 4K rpms.

Trip 2 - I swapped the prop to a good stainless 15 x 17p, and also swapped the powerpack incase that was limiting my RPMs. Vibrations are mostly gone, now hitting a top speed of 33mph and about 4,200 rpms. RPM and speed still seem very low for this boat. I'm told it should hit around 50mph and 5500 rpms. Same as last trip - ran 5 miles to the spot, anchored, ran back with no issues.

Trip 3 - This is where the main issue begins. I'm now switching fishing style to trolling. Run 8 miles to the spot, troll for 4hrs, then when I'm ready to leave and power up I have issues. It'll hop up on plane as usual, i'll get to cruising RPM around 3500-4000, and after a few seconds it starts acting up like it's not getting fuel. RPMs will drop a few thousand, i'll add some more throttle, because i'm confused.. then it loses so much power that it stalls out while I still have the throttle pinned. I try to start it a few times and it'll kick over and stall again. I pump the fuel primer bulb, get it running eventually, and we are back to cruising speed again. A few seconds later it starts acting up while at speed, and I squeeze the bulb more and it seems to clear up. At this point i'm able to run full tilt about 5 miles back without a hick up... My initial thoughts were that maybe it fouled the plugs and they had to clear out.

Trip 4 - Same as last trip, run to the spot, troll 4hrs, run back. The problem repeats itself almost exactly.

Trip 5 - After the last 2 trips I decide to inspect the fuel system for more than just leaks. I pull the whole pump / VRO assembly off to make sure i'm not missing something. Nothing obvious until I open the first chamber the fuel enters after the cone shaped filter. To my surprise I find a float / needle / seat just like a carb, and the needle is practically welded to the seat. I needed pliers to get it out. I replace these items and believe i've found the problem because this certainly wasn't functioning at all. Nope. I head out and run about 3 miles, idle and jig for a bit, run a few more miles, jig a bit more. Then I set up and troll for 4hrs, then when I get ready to head in here we go again - same shit. It loses power just like before, I get it running again and we get up to speed. It starts jumping around from 3500 to 4K rpms. I have my buddy steer and I start pumping the fuel bulb. It clears up and holds 4K , and we run full speed for 8 miles without a problem.

I'm running out of ideas what could be causing this, and unfortunately it takes hours of trolling to repeat the problem. I've run the service manual tests on the VRO and it clicks as it should with 15psi of pressure. Compression is also good.

Last edited by silverbullet87; 05-13-2019 at 06:24 AM.
Old 05-12-2019, 11:26 PM
  #2  
Admirals Club Admiral's Club Member
 
Join Date: Nov 2018
Posts: 13
Received 6 Likes on 4 Posts
Default

Sounds like a pin hole in your fuel line or bulb.
Old 05-12-2019, 11:34 PM
  #3  
Senior Member
 
Join Date: Feb 2019
Location: florida
Posts: 409
Likes: 0
Received 118 Likes on 75 Posts
Default

i would start with the fuel tank and work backwards. could be something that gets moved around in there and clogs then clears away.
then replace all rubber, screens, and filters to the engine. as well as draining the tank and system completely dry. and look around in the tank if you can.

older motors usually have older boats and lines involved so issues can be anywhere.

or you can replace one thing at a time to save a few bucks until one of those times you dont get back in.
Likes:
Old 05-13-2019, 01:51 AM
  #4  
Senior Member
 
Join Date: Apr 2006
Posts: 6,226
Received 1,403 Likes on 874 Posts
Default

How did you eliminate the idea of fouled plugs?
Old 05-13-2019, 04:06 AM
  #5  
Senior Member
 
Join Date: Nov 2012
Posts: 352
Received 62 Likes on 39 Posts
Default

honestly for a 2 stroke Johnson of that era that's kinda normal.... the plugs load up and foul after idling for hours (2 stroke carb motors dont want to idle.. theyre made to run) and it takes some time to clear them... try going to neutral about once an hour and rev her up to about 2k for 10-20 seconds at a time.. or even better, pull the lines and get on plane once an hour just for a minute or two.
Old 05-13-2019, 04:57 AM
  #6  
Senior Member
Thread Starter
 
Join Date: Mar 2014
Posts: 219
Likes: 0
Received 19 Likes on 17 Posts
Default

Originally Posted by Aliboy View Post
How did you eliminate the idea of fouled plugs?
I haven't 100% yet. I lean towards it being a fuel issue because when it was bouncing between 3500 and 4000 RPMs, squeezing the bulb immediately caused it to hold 4K steady. It reacted to having more fuel pushed in.

Originally Posted by fishbottom View Post
i would start with the fuel tank and work backwards. could be something that gets moved around in there and clogs then clears away.
then replace all rubber, screens, and filters to the engine. as well as draining the tank and system completely dry. and look around in the tank if you can.

older motors usually have older boats and lines involved so issues can be anywhere.

or you can replace one thing at a time to save a few bucks until one of those times you dont get back in.
I had just rebuilt this boat over the winter, and the tank was out and new fuel lines were installed. I agree though - i'm going to do that. I'll replace the anti syphon valve as well just incase. I'm confident there are no leaks past the fuel bulb at this point. I holds pressure very well when primed. Fuel bulb is new as well.

Originally Posted by Dan Apple View Post
honestly for a 2 stroke Johnson of that era that's kinda normal.... the plugs load up and foul after idling for hours (2 stroke carb motors dont want to idle.. theyre made to run) and it takes some time to clear them... try going to neutral about once an hour and rev her up to about 2k for 10-20 seconds at a time.. or even better, pull the lines and get on plane once an hour just for a minute or two.
I know that can happen, but it reacts to squeezing the fuel bulb so I have to lean towards a fuel delivery issue. Is bouncing around 500rpms a sign of fouled plugs? I wouldn't think so but maybe - i've never had fouled plugs before on a 2 stroke. I wonder if I need to pull the carbs and double check float settings.

Last edited by silverbullet87; 05-13-2019 at 05:53 AM.
Old 05-13-2019, 07:42 AM
  #7  
Senior Member
Thread Starter
 
Join Date: Mar 2014
Posts: 219
Likes: 0
Received 19 Likes on 17 Posts
Default

Originally Posted by Aliboy View Post
How did you eliminate the idea of fouled plugs?
I also feel like there is a fuel delivery issue in general due to the low max RPM. With a 15x17 prop I can't see why this motor is not spinning up over 4K. I ordered a inline spark tester to be sure all is well on the ignition side.
Old 05-13-2019, 07:50 AM
  #8  
Senior Member
 
Join Date: Nov 2012
Posts: 352
Received 62 Likes on 39 Posts
Default

Originally Posted by silverbullet87 View Post
I also feel like there is a fuel delivery issue in general due to the low max RPM. With a 15x17 prop I can't see why this motor is not spinning up over 4K. I ordered a inline spark tester to be sure all is well on the ignition side.
All that spark tester is going to tell you is whether or not the power pack is popping the plug at the right time (or at all) ... not anything at all about the plugs themselves....

I think you have multiple issues.... first you're trying to make a 2 stroke do something it doesnt want to do.... idling long periods (try what I suggested earlier about revving her up once in a while --it's free) AND Low max rpms on that engine most likely are due to the timing not advancing fully... What year is the engine? Is it one with the optical sensor? Do you have a book on the engine?

Find SEAHORSE on here.. he is an OMC guru
Old 05-13-2019, 07:55 AM
  #9  
Senior Member
 
Join Date: Jan 2002
Posts: 7,544
Received 813 Likes on 498 Posts
Default

You need to perform a fuel pressure test, boat fuel system vacuum test, and use a piece of clear fuel line at the pump inlet to monitor for air bubbles in the gas being drawn up by the pump. You have to run the boat at all speeds and especially where is surges to determine if the fuel system is at fault or if it marginal. Use a clip on timing light on each coil at the surging rpm and watch the timing marks to see if it is firing erratically or intermittently
Old 05-13-2019, 07:57 AM
  #10  
Senior Member
Thread Starter
 
Join Date: Mar 2014
Posts: 219
Likes: 0
Received 19 Likes on 17 Posts
Default

Originally Posted by Dan Apple View Post
All that spark tester is going to tell you is whether or not the power pack is popping the plug at the right time (or at all) ... not anything at all about the plugs themselves....

I think you have multiple issues.... first you're trying to make a 2 stroke do something it doesnt want to do.... idling long periods (try what I suggested earlier about revving her up once in a while --it's free) AND Low max rpms on that engine most likely are due to the timing not advancing fully... What year is the engine? Is it one with the optical sensor? Do you have a book on the engine?

Find SEAHORSE on here.. he is an OMC guru
Concerning the tester - I just want to make sure all are getting power because I know the motor should be spinning more RPMs. That is kinda separate of my falling on it's face issue.

I have the full service manual. It is fully advancing timing. It's a 97 or 98. (the sticker with the model # wore off)
Old 05-13-2019, 08:22 AM
  #11  
Senior Member
Thread Starter
 
Join Date: Mar 2014
Posts: 219
Likes: 0
Received 19 Likes on 17 Posts
Default

Originally Posted by seahorse View Post
You need to perform a fuel pressure test, boat fuel system vacuum test, and use a piece of clear fuel line at the pump inlet to monitor for air bubbles in the gas being drawn up by the pump. You have to run the boat at all speeds and especially where is surges to determine if the fuel system is at fault or if it marginal. Use a clip on timing light on each coil at the surging rpm and watch the timing marks to see if it is firing erratically or intermittently
Understood. I've been meaning to try the clear fuel line but until Saturday I thought I had fixed the problem. I just find it usual that it'll run full throttle after this issue occurs without a problem. It feels like the carbs get low on fuel while trolling, then when I power up there isn't enough fuel in the bulbs.

I'll rig up a fuel pressure test. Do you recall the pressures I should see at idle and at speed? I recall reading ~4-5 PSI in the manual.

How is a fuel system vacuum test performed? I have a mityvac but i'm not sure where you are suggesting I check. Disconnect @ the tank and test from there? I assume 15-20 PSI?

Thanks for the help.
Likes:
Old 05-13-2019, 09:09 AM
  #12  
Senior Member
Thread Starter
 
Join Date: Mar 2014
Posts: 219
Likes: 0
Received 19 Likes on 17 Posts
Default

Originally Posted by seahorse View Post
You need to perform a fuel pressure test, boat fuel system vacuum test, and use a piece of clear fuel line at the pump inlet to monitor for air bubbles in the gas being drawn up by the pump. You have to run the boat at all speeds and especially where is surges to determine if the fuel system is at fault or if it marginal. Use a clip on timing light on each coil at the surging rpm and watch the timing marks to see if it is firing erratically or intermittently
I might have misunderstood you on the vacuum test. I assume you mean put a gauge pre fuel pump to see if it's sucking properly? How much vacuum should I see?
Old 05-13-2019, 10:00 AM
  #13  
Admirals Club Admiral's Club Member
 
Join Date: Feb 2009
Posts: 1,676
Received 565 Likes on 272 Posts
Default

Had a plugged anti-siphon valve cause similar problems. Took it to my dealer, he knocked the AS valve out and called it good. And it was!
Old 05-13-2019, 10:47 AM
  #14  
Senior Member
Thread Starter
 
Join Date: Mar 2014
Posts: 219
Likes: 0
Received 19 Likes on 17 Posts
Default

Originally Posted by hjorgan View Post
Had a plugged anti-siphon valve cause similar problems. Took it to my dealer, he knocked the AS valve out and called it good. And it was!
I hear ya. I’ll probably just replace it to keep the safety feature.
Likes:
Old 05-18-2019, 10:59 AM
  #15  
Senior Member
Thread Starter
 
Join Date: Mar 2014
Posts: 219
Likes: 0
Received 19 Likes on 17 Posts
Default

Originally Posted by seahorse View Post
You need to perform a fuel pressure test, boat fuel system vacuum test, and use a piece of clear fuel line at the pump inlet to monitor for air bubbles in the gas being drawn up by the pump. You have to run the boat at all speeds and especially where is surges to determine if the fuel system is at fault or if it marginal. Use a clip on timing light on each coil at the surging rpm and watch the timing marks to see if it is firing erratically or intermittently
At idle, I have zero psi. Is that how it should be? I can’t get it show show pressure by revving either. I know the gauge is working because I can get pressure by pumping the fuel bulb. I won’t be back on the water until next weekend. To check at speed.
Old 05-18-2019, 11:02 AM
  #16  
Senior Member
Thread Starter
 
Join Date: Mar 2014
Posts: 219
Likes: 0
Received 19 Likes on 17 Posts
Default

Actually - I’m and idiot. Checked the wrong fuel line... rechecking now.
Old 05-18-2019, 01:50 PM
  #17  
Senior Member
 
Join Date: Feb 2019
Location: florida
Posts: 409
Likes: 0
Received 118 Likes on 75 Posts
Default

also most of the after market non original brand fuel bulbs arent the best. even a new one may not work.

also with some motors the fuel bulb wont work unless it is in a vertical position. that is important. and of course make sure the arrow is pointed the right way.

since pumping helps then it can be an air leak or possible no air getting to the fuel tank itself and needs vented.

sometimes fuel pumps go and act intermittently and drive you crazy. they are relatively cheap to replace compared to the anxiety.

of course pull plugs and look at them. never hurt to do that. and as said 2 strokes have problems from trolling too long with them.
Old 05-18-2019, 02:47 PM
  #18  
Senior Member
 
Join Date: Jul 2016
Location: titusville fl
Posts: 722
Received 519 Likes on 184 Posts
Default

Originally Posted by silverbullet87 View Post
Understood. I've been meaning to try the clear fuel line but until Saturday I thought I had fixed the problem. I just find it usual that it'll run full throttle after this issue occurs without a problem. It feels like the carbs get low on fuel while trolling, then when I power up there isn't enough fuel in the bulbs.
Thanks for the help.
I have a 2000 Johnson 250 and it was doing the same thing I changed a few parts trying to "find the bad part" and kept having the problem,I run 20 plus miles offshore fishing so I finally replaced all in the fuel system from the tank to the pump even if it was replaced in the last few months and it fixed it and have not had a problem in over a year.

I had just replaced the prime bulb and the fuel water filter but I still replaced both with everything else to make sure.The fuel bulb that time because it felt weird and had a crunch sound at times when you squeezed it.

Every time I had the problem with it losing power/shutting off all I had to do was reprime the fuel system and it was fine.Make sure you check the valves on the fuel tank even if the where just replaced.
Old 05-18-2019, 06:07 PM
  #19  
Senior MemberCaptains Club MemberPLEDGER
 
Join Date: Sep 2003
Location: CA & San Carlos, Mx
Posts: 22,858
Received 1,028 Likes on 674 Posts
Default

I had the same engine and it was flawless for 4 years until the tank vent salted over and when I tried a perko priming bulb instead of the oem part.
Go to a hotter plug for trolling. Retighten all fuel hose clamps
Old 05-19-2019, 07:34 AM
  #20  
Senior Member
 
Join Date: Nov 2004
Posts: 995
Received 73 Likes on 34 Posts
Default

Had same type of issue with an f150. Turns out the check valve in the priming bulb failed and had closed off all but a trifckle of fuel. Mechanic replaced it and all good.

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.