It is currently Thu Mar 28, 2024 9:21 am




Reply to topic  [ 7 posts ] 
 Intermitent problem 
Author Message
MMT Member

Joined: Thu Nov 22, 2012 3:17 pm
Posts: 14
Post Intermitent problem
Could use some help. Background 50 hrs on vanguard35hp GTR, clean fuel system (i think). Ran it dry, drained tank, for period of time between uses. Put in ethanol free gas with additive and took boat out it initially ran great but after about 45 minutes it started dying, missing, really knocking. back fires and loosing rpm's. I would put into neutral and it would rev and sound normal. I would put into drive and it would go through the same symptoms, than after a few minutes it would clear and run like a monster and than repeat itself. This happened on and off all afternoon, this was kind of a preseason run. I don't have much for shops where I live to help trouble shoot. The final episode thought I was going to have to paddle in.

After the last run I replaced the fuel filter, canister type, and the primer bulb so that everything between tank and engine is good. I run a pretty high end racing fuel line under the deck to the filter and engine. Like I said at idle or with out a load it seems to run fine, it backfires a little when turned off.
thanks


Sat Oct 14, 2017 4:27 pm
Profile
MMT Addict

Joined: Mon Jun 13, 2016 6:44 pm
Posts: 630
Post Re: Intermitent problem
When I had this problem, it was ethanol breaking down the inner liner of a fuel line. Ran great at idle, but as soon as you would take off, it would gradually lose power. This was due to the inner liner compressing, and starving motor of fuel.

Since you don't use ethanol and run a premium line it is probably not your issue.

Is the tank venting properly?

Sent from my SM-G920V using Tapatalk


Sun Oct 15, 2017 6:37 am
Profile
MMT 1000 Club
User avatar

Joined: Thu Nov 04, 2010 7:38 am
Posts: 4323
Location: Cut Off, La.
Post Re: Intermitent problem
X's 2^^


What about any intake leaks?

Did you pull the carb apart and inspect it?

You may have premium ful line, but make sure the inside isn't collapsed.

_________________
Refurbishing a Prodrive


Sun Oct 15, 2017 7:23 am
Profile
MMT Member

Joined: Thu Nov 22, 2012 3:17 pm
Posts: 14
Post Re: Intermitent problem
I have the junky red plastic boat gas tank, does everyone drill out the cap?


Sun Oct 15, 2017 12:31 pm
Profile
MMT Member

Joined: Thu Nov 22, 2012 3:17 pm
Posts: 14
Post Re: Intermitent problem
sorry, I did not take the carb apart. I did sprAY cleaner in the intake.


Sun Oct 15, 2017 12:33 pm
Profile
MMT Pro Member

Joined: Sun Feb 20, 2011 4:14 pm
Posts: 95
Post Re: Intermitent problem
spark plug boots have any cracks? Both coils firing?


Sun Oct 15, 2017 2:53 pm
Profile
MMT 1000 Club
User avatar

Joined: Thu Nov 04, 2010 7:38 am
Posts: 4323
Location: Cut Off, La.
Post Re: Intermitent problem
Drill out the white ball in the cap of tank, and pull carb and clean thoroughly.
Confirm fuel hose isn't collapsed.
If all is good there, then check for spark, and spark plug wires arcing out like mentioned above.

_________________
Refurbishing a Prodrive


Sun Oct 15, 2017 4:53 pm
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 7 posts ] 

Who is online

Users browsing this forum: No registered users and 184 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to: